Polyurethanes containing amino organosilane modified clay

This invention relates to polyurethane polymer compositions containing finely divided amino organosilane modified kaolin clay fillers.

The present application is a continuation-in-part of applicant's copending application Ser. No. 269,695, filed Apr. 1, 1963, now Patent No. 3,290,165, entitled, "Surface Modified Pigments," which in turn is a continuation-in-part of applicant's application Ser. No. 189,321, filed Apr. 23, 1962, entitled, "Surface Modified Pigments," now abandoned.

Polyurethane polymer compositions can be formed from a variety of polymers, l.e., thermosetting gums, thermoplastic polymers and liquid or casting polymers. The preparations for various classes and grades of polyurethanes are well known in the art and need not be detailed here; however, the general reaction by which they are formed is by a chain extension process rather than the usual polymerization reaction. In this process a relatively short chain polymer, either a polyester or a polyether, is reacted with an organic diisocyanate to form long chain urethane polymer. The process variations and polymerization variations caused thereby result in a multitude of compositions all broadly falling in one of the three classes mentioned.

The polyurethanes have several outstanding properties which make them desirable products, chief among them is abrasion resistance, good low temperature characteristics, good resistance to heat deterioration, ozone cracking, weathering, and oil or solvent swelling.

Thermosetting gum vulcanizates have a variety of uses in conveyor belts, roll covers, sandblast-hose tubes and other applications where good abrasion resistance is needed.

Thermoplastic resins can be processed on standard extrusion, injection molding, and transfer molding equipment. These resins are useful in small parts such as mallet heads, sprocket gears, adhesive coatings and unsupported sheetings such as fuel tanks, tarpaulins and chute liners.

Liquid polyurethane valcanizates exhibit good abrasion resistance, non-marking and a wide range of hardnesses. These products have use in large rolls for the steel industry, fork lift truck wheels, ladies toplifts, ball-joint seals, automotive seals, potting compounds, conveyor belts, V-belts, and tank linings.

Despite the fact that the polyurethanes have outstanding properties and are suitable for a large variety of uses, industry is constantly attempting to improve them by various means. Properties which are desirable to improve are modulus, tear resistance, hardness and abrasion resistance. In many cases reinforcing fillers have been tried but on the whole, while some improvements resulted, the degradation of other properties resulted and a completely satisfactory filler has not been found.

It is an object of this invention to provide solid polyprethane vulcanizates and thermoplastic resin compositions containing reinforcing fillers of modified kaolin clays.

Other objects and advantages will be apparent from the following specification.

I have discovered that kaolin clay modified with saturated amino organosilanes are reinforcing fillers for polyurethane polymers and impart improved properties to them. Particularly, modulus and tear resistance are improved with little, if any, degradation of other important properties.

The kaoline clays which are suitable as substrates for the modifier are refined clays of the rubber and paper grades.

The modified kaolin clays can be prepared by dissolving the desired amount of amino organosilane in a suitable solvent, adding the pigment and heating until the reaction is complete. The amount of modifier added depends upon the specific modifier used and the intended polymer to be reinforced. Generally from 1% to 3% by weight of the modifier is sufficient for most purposes.

A particularly useful process for modifying the kaolin clay involves spray drying kaolin slurries having one or more of the amino organosilanes dispersed therein. The spray drying process effects a uniform distribution of the modifier on the kaolin. Another satisfactory method of modifying the kaolin involves dissolving the desired amount of amino organosilane in a suitable solvent, adding the kaolin and heating until the reaction is complete.

The compounds used to modify the kaolin clays can be depicted by the formula: ##STR1## wherein R 1 is hydrogen, alkyl, aryl, cycloalkyl, or alkylaryl; R 2 is hydrogen, alkyl, aryl, cycloalkyl, or alkylaryl; R 3 is hydrogen, lower alkyl, aryl, lower alkylaryl, or lower arylalkyl; R 4 is hydrogen, lower alkyl, aryl, lower alkylaryl, or lower arylalkyl; R 5 is hydrogen, lower alkyl, aryl, lower alkylaryl, or lower arylalkyl; and X is alkylene, alkylene containing secondary amino nitrogen, alkylene containing tertiary amino nitrogen, arylene, arylene containing secondary amino nitrogen, arylene containing tertiary amino nitrogen, alkylarylene, alkylarylene containing secondary amino nitrogen, alkylarylene containing tertiary amino nitrogen, arylalkylene, arylalkylene containing secondary amino nitrogen, arylalkylene containing tertiary amino nitrogen, cycloalkylene, cycloalkylene containing secondary amino nitrogen and cycloalkylene containing tertiary amino nitrogen. Some of these amino organosilanes are disclosed along with methods for their preparation in U.S. Patents Nos. 2,832,754, 2,930,809, 3,007,957, and 3,020,302. Commercially available amino organo silanes useful in the practice of this invention include "A-1100," a gamma-aminopropyltriethoxy silane (GAPTS), and "Y-2967," an amino organosilane which is a modified gamma-aminopropyltriethoxy silane, sold by Union Carbide Corporation, New York, N.Y., "Z-6020," a diamino functional silane, sold by Dow Corning Corporation, Midland, Michigan.

Representative commercially available polyurethane polymers suitable for use in this invention are "Vibrathane 5003," a thermosetting gum which is cross-linked, produced by Naugatuck Chemical Division of U.S. Rubber Company; "Elastothane 455," a thermosetting gum which is cross-linked, produced by Thiokol; "Genthane S," a cross-linked thermosetting gum produced by General Chemical; "Estane," a thermoplastic resin produced by B. F. Goodrich Chemical; "Texin," a thermoplastic resin produced by Mobay; "Multrathane," a liquid polymer produced by Mobay; "Cyanoprene 4590," a liquid polymer produced by American Cyanamid; "Adiprene L," produced by Du Pont; "Vibrathane 6000," produced by Naugatuck; and "Neothane," produced by Goodyear.

In the following formulations the gums were mill-mixed or Banbury-mixed and the thermoplastic resins were mill-mixed and injection molded.

The following formulations illustrate this invention.

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Parts

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Vibrathane 5003 100

Stearic acid 0.25

Dicup 40C (polymerizing agent)

5

Filler (modified clay)

60

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The compounds were mixed on a 6 inch by 12 inch laboratory mill and cured for 30 minutes at 307° F., except for the NBS abrasion test where the cure was for 60 minutes at 307° F.

The data tabulated in Table I indicates the results when 1%, 2% and 3% by weight of GAPTS modified kaolin clay and 1% by weight Silicone Z-6020 modified kaolin clay is the filler.

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1% 2% 3% 1%

GAPTS GAPTS GAPTS Z-6020

Control

Kaolin

on Kaolin

on Kaolin

on Kaolin

on Kaolin

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Parts Filler/100 parts Polymer

None 60 60 60 60 60

Tensile, p.s.i. 3,500

(.sup.1)

3,920 3,600 3,840 3,270

Stress 300%, p.s.i.

1,040

(.sup.1)

2,600 3,390 -- 2,520

Elongation, percent

440 (.sup.1)

470 350 265 365

Shore A Hardness 58 -- 74 74 74 73

NBS Abrasion, percent of Standard

100 -- 89 134 157 193

Minutes Cured at 305° F.

30 30 30 30 30 60

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.sup.1 No cure.

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Parts

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Texin 480A

100

Modified clay

20

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The resin was molded at 390°-410° F. and post cured at 110° C. for 24 hrs. The results are tabulated in Table II.

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1%

Con- Kao- GAPTS

trol lin on Kaolin

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Parts Filler/100 parts Polymer

None 20 20

Stress 300%, p.s.i. 1,720 2,170 2,430

Tensile, p.s.i. 5,700 2,540 2,620

Elongation, percent 640 510 400

Shore A Hardness 75 78 78

NBS Abrasion, percent of Standard

100 77 92.5

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Parts

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Texin 480A

100

Modified clay

20

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The resin was molded at 390°-410° F. and was not post cured. The results are shown in Table III.

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0.25% 0.5% 1%

Con- Kao- on on on

trol lin Kaolin Kaolin Kaolin

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Parts Filler/100

0 20 20 20 20

parts Polymer

Stress 300%, p.s.i.

1,090 1,680 1,725 1,735 1,720

Tensile, p.s.i.

4,380 4,470 3,340 4,250 4,400

Elongation,

610 640 560 655 595

percent

Shore A Hardness

85 88 88 88 88

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Parts

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Estane 5701 100

Barium stearate 3

Modified clay 25 or 50

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The resin was molded 5' at 350° F. held in the mold under pressure until the temperature dropped below 200° F. The results are tabulated in Table IV.

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Con- Kaolin plus

trol Kaolin 1% Z 6020

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Parts Filler/100 parts Polymer

0 25 50 25 50

300% Modulus, p.s.i.

1,220 1,580 1,640

2,840

3,300

ASTM Test "Die" C, lbs./in

410 500 300 560 580

NBS Abrasion Index, percent

492 521 720 1,285

16.72

NBS Abrasion Shore A

82 90 92 90 92

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Parts

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Estane 5701 100

Barium stearate

3

Filler 25, 50 or 100

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The polymer batch was treated as in Example IV. The results are shown in Table V.

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Kaolin

Kaolin

Kaolin

Kaolin Kaolin

Kaolin Kaolin

Kaolin

Con-

Kao-

plus 2%

plus 2%

plus 3%

plus 1%

Kao-

plus 2%

plus 1%

Kao-

plus

plus 1%

trol

lin

Z 6020

lin

Z 6020

lin

Z

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6020

Parts Filler/100 parts

0 25 25 25 25 25 50 50 50 100

100 100

Polymer

200% Modulus, p.s.i.

860

-- -- -- -- -- 1,700

3,500

3,740

-- -- --

300% Modulus, p.s.i.

1,440

1,780

2,940

3,260

3,040

3,000

-- -- -- -- -- --

Shore A Hardness

88 93 91 92 91 91 94 94 95 97 97 97

NBS Abrasion, Index

460

641

827 703 641 746 624

936 568 334

553 575

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Parts

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Estane 5701 100

Barium Stearate 3

Pigment 25 or 50

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The recipe was treated the same as in Example IV. The results are shown in Table VI.

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Kaolin Kaolin

plus plus

Con- Kao- 2% 1%

trol lin GAPTS Z-6020

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Parts Filler/100

None 25 50 25 50 25 50

parts Polymer

300% Modulus,

1,220 1,580 1,640

2,880

3,600

2,840

3,300

p.s.i.

ASTM Tear "Die

410 500 500 550 480 560 580

C," lbs./in

NBS Abrasion,

492 521 720 1,015

1,411

1,285

1,672

Index percent

NBS Abrasion,

82 90 92 90 91 90 92

Shore A Hardness

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Parts

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Estane 5701 100

Barium Stearate

3

Filler 10, 20, 60 or 100

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The recipe was treated as in Example IV. The results are shown in Table VII.

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Con-

Kaolin Plus

Kao-

Kaolin Plus

Kao- -trol 1% Z-6020 lin 1%

Z-6020 lin

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Parts Filler/100 parts Polymer

0 10 20 20 60 100 100

300% Modulus, p.s.i.

1,280

2,040

2,740

1,640

3,420

-- 2,040

ASTM Tear "Die C," lbs./in

420 500

600 530 540

406 510

NBS Abrasion, Index percent

570 867

1,095

957 1,722

1,465

717

NBS Abrasion, Shore A

84 85 89 89 94 95 95

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Parts

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Adiprene L-100 100

Methylene-bis-orthochloraniline

11

Pigment 20

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The mixture was cured for 180 minutes at 212° F. The results are shown in Table VIII.

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Kaolin

Plus 1%

Control

Kaolin Z-6020

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Parts Filler/100 parts Polymer

0 20 20

300% Modulus, p.s.i.

1,530 -- 1,940

Tensile, p.s.i. 2,570 1,310 2,710 -Elongation, Percent 495 285 480

5

Shore A Hardness 87 88 90

ASTM Tear "Die C," lbs./in

450 408 505

NBS Abrasion, Index Percent

224 126 194

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The examples and data indicate that when the modified kaolin clays useful in this invention are used as fillers in thermosetting gum polyurethanes increases in modulus, hardness and abrasion resistance occur. The remaining properties of the polymer remain within acceptable levels. When these fillers are used to reinforce thermoplastic resins, increases in modulus, tear resistance, and abrasion resistance occur while the remaining polymer properties remain within acceptable levels. When these modified kaolin clay fillers are used to reinforce liquid polymers, increases in modulus, tensile strength, hardness, and tear resistance occur while the remaining properties of the polyurethane remain within acceptable levels. In all the polymers tested the general level of performance of the modified kaolins was superior to the unmodified kaolins.

The foregoing is illustrative only and additional modifications may be made without departing from the substance of the invention as defined in the appended claims.