Self-hardening organic synthetic resin mixture used for additive manufacturing, and application therefor

Stage 1: Preparation of Linear Thermoplastic Phenolic Resin

The raw materials for the linear thermoplastic phenolic resin was shown in Table 1.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) 30% by weight of a phenolic compound, 0.5% by weight of an organic acid as a catalyst and 2.5% by weight of a polymerization inhibitor were added to an enamel reactor followed by stirring, and then 45% by weight of an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and 18% by weight of an organic solvent, 0.4% by weight of a toughening agent and 3% by weight of a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and 0.6% by weight of silane as a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of Phenol Modified Furan Resin

The raw materials for the phenol modified furan resin was shown in Table 2.

Process of producing the phenol modified furan resin was described as follows.

(1) 20% by weight of a phenolic compound, 10% by weight of an aldehyde compound and 0.8% by weight of an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., 25% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then 0.5% by weight of a pH regulator was added to the enamel reactor to adjust pH of the mixture to about 5.7-6.0, and 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., 6% by weight of an organic waste liquid, 0.4% by weight of a heat stabilizer and 6% by weight of additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and 10% by weight of a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and 0.5% by weight of an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and 0.8% by weight of water-based silane as a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

35% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 65% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

The self-curing organic synthetic resin composition prepared by this method has a viscosity of 11.5 mpa·s at 25° C., a surface tension of 34 mN/s at 20° C., an impurity content of 0.04%, a free formaldehyde content of 0.12% and a density of 1.086 g/ml at 20° C. It has a tensile strength of 2.16 MPa at normal temperature for 24 h, a tensile strength of 1.32 MPa at 1000° C. and a residual tensile strength of 0.12 MPa at 1000° C. It has a usable life of 1.2 min at 25° C.

Stage 1: Preparation of Linear Thermoplastic Phenolic Resin

The raw materials for the linear thermoplastic phenolic resin was shown in Table 3.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) 35% by weight of a phenolic compound, 0.3% by weight of an organic acid salt as a catalyst and 3% by weight of a molecular polymerization inhibitor were added to an enamel reactor followed by stirring, and then 40% by weight of an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and 17% by weight of an organic solvent, 0.3% by weight of a toughening agent and 4% by weight of a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and 0.4% by weight of silane as a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of Phenol Modified Furan Resin

The raw materials for the phenol modified furan resin was shown in Table 4.

Process of producing the phenol modified furan resin was described as follows.

(1) 15% by weight of a phenolic compound, 10% by weight of an aldehyde compound and 0.8% by weight of an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., 30% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then 0.5% by weight of a pH regulator was added to the enamel reactor to adjust pH of the mixture to about 5.7-6.0, and 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., 6% by weight of an organic waste liquid, 0.4% by weight of a heat stabilizer and 8% by weight of an additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and 10% by weight of a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and 0.5% by weight of an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and 0.8% by weight of water-based silane as a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

30% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 70% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

The self-curing organic synthetic resin composition prepared by this method has a viscosity of 12.0 mpa·s at 25° C., a surface tension of 33 mN/s at 20° C., an impurity content of 0.036%, a free formaldehyde content of 0.16% and a density of 1.105 g/ml at 20° C. It has a tensile strength of 2.24 MPa at normal temperature for 24 h, a tensile strength of 1.26 MPa at 1000° C. and a residual tensile strength of 0.15 MPa at 1000° C. It has a usable life of 1.4 min at 25° C.

Stage 1: Preparation of Linear Thermoplastic Phenolic Resin

The raw materials for the linear thermoplastic phenolic resin was shown in Table 5.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) 40% by weight of a phenolic compound, 0.4% by weight of an organic acid or an organic acid salt as a catalyst and 2.5% by weight of a molecular polymerization inhibitor were added to an enamel reactor followed by stirring, and then 35% by weight of an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and 16% by weight of an organic solvent, 0.6% by weight of a toughening agent and 5% by weight of a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and 0.5% by weight of silane as a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of Phenol Modified Furan Resin

The raw materials of the phenol modified furan resin was shown in Table 6.

Process of producing the phenol modified furan resin was described as follows.

(1) 14% by weight of a phenolic compound, 13% by weight of an aldehyde compound and 0.6% by weight of an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., 30% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then 11% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then 0.4% by weight of a pH regulator was added to the enamel reactor to adjust pH of the mixture to about 5.7-6.0, and 11% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., 4% by weight of an organic waste liquid, 0.5% by weight of a heat stabilizer and 4% by weight of an additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and 10% by weight of a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and 0.4% by weight of an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and 1.1% by weight of water-based silane as a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

40% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 60% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

The self-curing organic synthetic resin composition prepared by this method has a viscosity of 10.8 mpa·s at 25° C., a surface tension of 36 mN/s at 20° C., an impurity content of 0.043%, a free formaldehyde content of 0.19% and a density of 1.066 g/ml at 20° C. It has a tensile strength of 2.09 MPa at normal temperature for 24 h, a tensile strength of 1.35 MPa at 1000° C. and a residual tensile strength of 0.14 MPa at 1000° C. It has a usable life of 1.6 min at 25° C.

Stage 1: Preparation of Linear Thermoplastic Phenolic Resin

The raw materials for the linear thermoplastic phenolic resin was shown in Table 7.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) 30% by weight of a phenolic compound, 0.5% by weight of an organic acid or an organic acid salt as a catalyst and 2% by weight of a molecular polymerization inhibitor were added to an enamel reactor followed by stirring, and then 40% by weight of an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and 24% by weight of an organic solvent, 0.7% by weight of a toughening agent and 2% by weight of a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and 0.8% by weight of silane as a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of Phenol Modified Furan Resin

The raw materials for the phenol modified furan resin was shown in Table 8.

Process of producing the phenol modified furan resin was described as follows.

(1) 20% by weight of a phenolic compound, 10% by weight of an aldehyde compound and 1% by weight of an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., 25% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then 0.4% by weight of a pH regulator was added to the enamel reactor to adjust pH of the mixture to about 5.7-6.0, and 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., 5% by weight of an organic waste liquid, 0.5% by weight of a heat stabilizer and 4.5% by weight of an additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and 12% by weight of a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and 0.3% by weight of an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and 1.3% by weight of water-based silane as a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

32% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 68% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

The self-curing organic synthetic resin composition prepared by this method has a viscosity of 12.6 mpa·s at 25° C., a surface tension of 33 mN/s at 20° C., an impurity content of 0.051%, a free formaldehyde content of 0.21% and a density of 1.114 g/ml at 20° C. It has a tensile strength of 2.20 MPa at normal temperature for 24 h, a tensile strength of 1.27 MPa at 1000° C. and a residual tensile strength of 0.17 MPa at 1000° C. It has a usable life of 1.5 min at 25° C.

Stage 1: Preparation of Linear Thermoplastic Phenolic Resin

The Raw materials for the linear thermoplastic phenolic resin was shown in Table 9.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) 38% by weight of a phenolic compound, 0.2% by weight of an organic acid or an organic acid salt as a catalyst and 2% by weight of a molecular polymerization inhibitor were added to an enamel reactor followed by stirring, and then 44% by weight of an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and 13% by weight of an organic solvent, 0.4% by weight of a toughening agent and 2% by weight of a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and 0.4% by weight of silane as a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of Phenol Modified Furan Resin

The Raw materials for the phenol modified furan resin was shown in Table 10.

Process of producing the phenol modified furan resin was described as follows.

(1) 25% by weight of a phenolic compound, 8% by weight of an aldehyde compound and 0.5% by weight of an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., 30% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then 0.4% by weight of a pH regulator was added to the enamel reactor to adjust pH of the mixture to about 5.7-6.0, and 10% by weight of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., 0.5% by weight of a heat stabilizer and 6.5% by weight of an additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and 8% by weight of a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and 0.5% by weight of an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and 0.6% by weight of water-based silane as a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

34% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 66% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

The self-curing organic synthetic resin composition prepared by this method has a viscosity of 11.9 mpa·s at 25° C., a surface tension of 32 mN/s at 20° C., an impurity content of 0.024%, a free formaldehyde content of 0.22% and a density of 1.124 g/ml at 20° C. It has a tensile strength of 2.28 MPa at normal temperature for 24 h, a tensile strength of 1.35 MPa at 1000° C. and a residual tensile strength of 0.11 MPa at 1000° C. It has a usable life of 1.6 min at 25° C.

The self-curing organic synthetic resin composition was prepared through three stages. In which, a linear thermoplastic phenolic resin prepared in stage (1) and a phenol modified furan resin prepared in stage (2) were mixed in a certain weight ratio in stage (3) to obtain the self-curing organic synthetic resin composition for additive manufacturing.

Stage 1: Preparation of the Linear Thermoplastic Phenolic Resin

The raw materials for the linear thermoplastic phenolic resin was shown in Table 11.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) A phenolic compound, an organic acid or an organic acid salt as a catalyst, and a molecular polymerization inhibitor were added to an enamel reactor followed by stirring, and then an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and an organic solvent, a toughening agent and a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of the Phenol Modified Furan Resin

The raw materials for the phenol modified furan resin was shown in Table 12.

Process of producing the phenol modified furan resin was described as follows.

(1) A phenolic compound, an aldehyde compound and an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., half of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then a quarter of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then a pH regulator was added to the enamel reactor, and a quarter of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., an organic waste liquid, a heat stabilizer and an additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of the Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

30% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 70% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

Compared to Example 6, Example 7 used different raw materials of a linear thermoplastic phenolic resin (as shown in Table 13) and different raw materials of a phenol modified furan resin (as shown in Table 14).

Methods for preparing the linear thermoplastic phenolic resin, the phenol modified furan resin and a self-curing organic synthetic resin composition for additive manufacturing in Example 7 were the same as those in Example 6.

Compared to Example 6, Example 8 used different raw materials of a linear thermoplastic phenolic resin (as shown in Table 15) and different raw materials of a phenol modified furan resin (as shown in Table 16).

Methods for preparing the linear thermoplastic phenolic resin, the phenol modified furan resin and a self-curing organic synthetic resin composition for additive manufacturing in Example 8 were the same as those in Example 6.

Compared to Example 6, Example 9 used different raw materials of a linear thermoplastic phenolic resin (as shown in Table 17) and different raw materials of a phenol modified furan resin (as shown in Table 18).

Methods for preparing the linear thermoplastic phenolic resin, the phenol modified furan resin and a self-curing organic synthetic resin composition for additive manufacturing in Example 9 were the same as those in Example 6.

Compared to Example 6, Example 10 used different raw materials of the linear thermoplastic phenolic resin (as shown in Table 19) and different raw materials of the phenol modified furan resin (as shown in Table 20).

Methods for preparing the linear thermoplastic phenolic resin, the phenol modified furan resin and a self-curing organic synthetic resin composition for additive manufacturing in Example 10 were the same as those in Example 6.

Compared to Example 6, Example 11 used different raw materials of the linear thermoplastic phenolic resin (as shown in Table 21) and different raw materials of the phenol modified furan resin (as shown in Table 22).

Methods for preparing the linear thermoplastic phenolic resin, the phenol modified furan resin and a self-curing organic synthetic resin composition for additive manufacturing in Example 11 were the same as those in Example 6.

Compared to Example 6, Example 12 used different raw materials of the linear thermoplastic phenolic resin (as shown in Table 23) and different raw materials of the phenol modified furan resin (as shown in Table 24).

Methods for preparing the linear thermoplastic phenolic resin, the phenol modified furan resin and a self-curing organic synthetic resin composition for additive manufacturing in Example 12 were the same as those in Example 6.

In conclusion, the self-curing organic synthetic resin composition was prepared through three stages. In which, the linear thermoplastic phenolic resin prepared in stage (1) and the phenol modified furan resin prepared in stage (2) were mixed in a certain weight ratio in stage (3) to obtain the self-curing organic synthetic resin composition for additive manufacturing.

Stage 1: Preparation of the Linear Thermoplastic Phenolic Resin

The raw materials for the linear thermoplastic phenolic resin was shown in Table 25.

Process of producing the linear thermoplastic phenolic resin was described as follows.

(1) A phenolic compound, an organic acid or an organic acid salt as a catalyst, and a molecular polymerization inhibitor were added to an enamel reactor followed by stirring, and then an aldehyde compound was added to the enamel reactor.

(2) A steam valve was opened to heat the mixture, and the temperature raised to 85-90° C. in 25-30 min and was maintained at 85-90° C. for 30-40 min.

(3) The temperature further raised to 100-105° C. in 10-20 min and was maintained at 100-105° C. for 120-150 min.

(4) The mixture was subjected to vacuum dehydration until a desired level of dehydration was reached.

(5) The temperature was dropped to 70-75° C., and an organic solvent, a toughening agent and a modifier were added to the enamel reactor followed by stirring for 60-90 min.

(6) The temperature was further dropped to 30-35° C., and a coupling agent was added to the enamel reactor followed by stirring for 40-60 min. The mixture prepared herein was unloaded for use.

Stage 2: Preparation of the Phenol Modified Furan Resin

The raw materials for the phenol modified furan resin was shown in Table 26.

Process of producing the phenol modified furan resin was described as follows.

(1) A phenolic compound, an aldehyde compound and an organic acid as a catalyst were added to an enamel reactor followed by stirring.

(2) A steam valve was opened to heat the mixture, and after the temperature raised to 70-75° C., half of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 70-75° C. for 55-60 min.

(3) The temperature raised to 80-85° C. in 10-20 minutes, and then a quarter of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 80-85° C. for 60-90 min.

(4) The temperature raised to 95-100° C. in 10-20 minutes, and then a pH regulator was added to the enamel reactor, and a quarter of furfuryl alcohol was added to the enamel reactor, and the temperature was maintained at 95-100° C. for 120-150 min.

(5) At 95-100° C., an organic waste liquid, a heat stabilizer and an additive were added to the enamel reactor followed by stirring for 50-60 min.

(6) The temperature was dropped to 60-65° C., and a diluent was added to the enamel reactor followed by stirring for 30-60 min.

(7) The temperature was dropped to 40-45° C., and an aldehyde trapping agent was added to the enamel reactor followed by stirring for 30-60 min.

(8) The temperature was dropped to 30-35° C., and a coupling agent was added to the enamel reactor followed by stirring for 30-60 min. The mixture prepared herein was unloaded for use.

Stage 3: Preparation of the Self-Curing Organic Synthetic Resin Composition for Additive Manufacturing

30% by weight of the linear thermoplastic phenolic resin prepared in stage (1) and 70% by weight of the phenol modified furan resin prepared in stage (2) were added to an enamel reactor followed by stirring. Then, the temperature raised to 35-40° C. and was maintained at 35-40° C. for 60-90 min. The mixture prepared herein was unloaded, tested and packaged to obtain the self-curing organic synthetic resin composition for additive manufacturing.

The self-curing organic synthetic resin composition was used for additive manufacturing in the presence of a water-soluble or alcohol-soluble acidic solution.

In 3D additive manufacturing, the water-soluble or alcohol-soluble acidic solution was an alcoholic sulfonic acid solution having a total acidity of 32% and a free acid of 5% or less. The alcoholic sulfonic acid solution was 20% by weight of the self-curing organic synthetic resin composition for additive manufacturing.

During 3D printing process, the alcoholic sulfonic acid solution was uniformly mixed with raw sand materials to obtain a mixture. A layer of the mixture was laid onto a printing table, and then sprayed with the self-curing organic synthetic resin composition by a piezoelectric printhead according to a 3D model designed by a computer program. Due to the reaction between the self-curing organic synthetic resin composition and the alcoholic sulfonic acid solution applied on surfaces of the raw sand materials, the layer was rapidly cured at normal temperature. Then a next layer of the mixture was laid down over previous layers followed by spraying the self-curing organic synthetic resin composition and curing. The processes of laying, spraying and curing were repeated until a top layer was completed. Raw sand materials from unprinted areas were removed to obtain a 3D printed final product.

The self-curing organic synthetic resin composition prepared herein had advantages of high strength at normal temperature, excellent resistance to high temperature, high activity and good collapsibility, so a casting mold could be printed by 3D additive manufacturing for casting purpose, and the casting mold printed herein was suitable for casting various metal workpieces, greatly facilitating casting production.

The self-curing organic synthetic resin composition was used for additive manufacturing in the presence of a water-soluble or alcohol-soluble acidic solution.

In 3D additive manufacturing, the water-soluble or alcohol-soluble acidic solution was an aqueous sulfonic acid solution having a total acidity of 16% and a free acid of 5% or less. The aqueous sulfonic acid solution was 60% by weight of the self-curing organic synthetic resin composition for additive manufacturing.

During 3D printing process, the aqueous sulfonic acid solution was uniformly mixed with raw sand materials to obtain a mixture. A layer of the mixture was laid onto a printing table, and then sprayed with the self-curing organic synthetic resin composition by a piezoelectric printhead according to a 3D model designed by a computer program. Due to the reaction between the self-curing organic synthetic resin composition and the aqueous sulfonic acid solution applied on surfaces of the raw sand materials, the layer was rapidly cured at normal temperature. Then a next layer of the mixture was laid down over previous layers followed by spraying the self-curing organic synthetic resin composition and curing. The processes of laying, spraying and curing were repeated until a top layer was completed. Raw sand materials from unprinted areas were removed to obtain a 3D printed final product.

The self-curing organic synthetic resin composition was used for additive manufacturing in the presence of a water-soluble or alcohol-soluble acidic solution.

In 3D additive manufacturing, the water-soluble or alcohol-soluble acidic solution was an aqueous or alcoholic sulfonic acid solution having a total acidity of 16-32% and a free acid of 5% or less. The aqueous or alcoholic sulfonic acid solution was 20-60% by weight of the self-curing organic synthetic resin composition for additive manufacturing.

During 3D printing process, the aqueous or alcoholic sulfonic acid solution was uniformly mixed with raw sand materials to obtain a mixture. A layer of the mixture was laid onto a printing table, and then sprayed with the self-curing organic synthetic resin composition by a piezoelectric printhead according to a 3D model designed by a computer program. Due to the reaction between the self-curing organic synthetic resin composition and the aqueous or alcoholic sulfonic acid solution applied on surfaces of the raw sand materials, the layer was rapidly cured at normal temperature. Then a next layer of the mixture was laid down over previous layers followed by spraying the self-curing organic synthetic resin composition and curing. The processes of laying, spraying and curing were repeated until a top layer was completed. Raw sand materials from unprinted areas were removed to obtain a 3D printed final product.

Some information is concluded from the above-mentioned embodiments.

(1) The self-curing organic synthetic resin composition has a viscosity of 10-14 mpa·s at 25° C., which meets the requirement of additive manufacturing.

(2) The self-curing organic synthetic resin composition has a high tensile strength at normal temperature (above 2.0 MPa), while under the same conditions, the self-curing furan resin has a tensile strength of only 1.4 MPa at normal temperature, and the self-curing sodium silicate binder and the self-curing basic phenolic resin share the tensile strength of only 1.2 MPa at normal temperature.

(3) The self-curing organic synthetic resin composition has excellent resistance to high temperature, since it has a tensile strength of over 1.2 MPa at 1000° C., while under the same conditions, the self-curing furan resin has a tensile strength of only 0.15 MPa at 1000° C.

(4) The self-curing organic synthetic resin composition has high activity, since it reacts quickly with an aqueous or alcoholic sulfonic acid solution having a total acidity of 16-32% and a free acid of 5% or less. During the reaction, it has a usable life in the range of 0.5-2 min at sand temperature of 25° C. While under the same conditions, the self-curing furan resin and the self-curing sodium silicate binder each react with the aqueous or alcoholic sulfonic acid solution having a total acidity of 16-32% and a free acid of 5% or less. During the reaction, the self-curing furan resin has a usable life in the range of 3-7 min, and the self-curing sodium silicate binder has a usable life in the range of 5-15 min.

(5) The self-curing organic synthetic resin composition has a residual tensile strength of 0.2 MPa or less at 1000° C. Under the same conditions, the self-curing sodium silicate binder has a residual tensile strength of about 0.5 Mpa at 1000° C. The contrast proves that the self-curing organic synthetic resin composition has excellent collapsibility, resulting in an easy sand cleaning process in the late stage of casting production.

(6) An organic waste liquid which is generated during 3D inkjet printing in casting is reapplied to the resin system, reducing the cost of resin production and use, and reducing the environmental pollution.

(7) Syrup and fructose, as eco-friendly materials, are introduced into the self-curing organic synthetic resin composition to partially replace furfuryl alcohol in raw materials, facilitating the environmental protection.

(8) The self-curing organic synthetic resin composition is stable, and after a long-term storage, there is neither crystal formation nor changes in performance and indexes.

The embodiments above are not intended to limit the present invention. Any substitutions and changes made by those skilled in the art based on the embodiments disclosed herein without any creative efforts, should fall within the scope of the invention.