CROSSLINKABLE RUBBER COMPOSITION, THE USE THEREOF, THE RUBBER GRAINS THEREFROM, AND A METHOD FOR PREPARING AND INJECTION MOLDING THE RUBBER GRAINS

• US 20120041130A1
• Filed: 07/30/2009
• Published: 02/16/2012
• Est. Priority Date: 03/10/2009
• Status: Abandoned Application

• Current Assignee: Shanghai DRB&Tafu Industry Co., Ltd.
• Original Assignee: Shanghai Drb&Tafu Industry Company
• Inventors: Ye, Sunyong
• Application Number:
  US13/255,872
• Publication Number:
  US 20120041130A1
• Time in Patent Office: Days
• US Class Current: 524/524
• CPC Class Codes: B29B 9/06 in the form of filamentary material, e.g. combined with extrusion
• CPC Class Codes: B29B 9/12 characterised by structure or composition
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 45/0001 characterised by the choice of material
• CPC Class Codes: B29C 48/0022 combined with cutting
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/04 Particle-shaped making granules B29B9/00
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: C08K 5/01 Hydrocarbons C08K5/0091 takes precedence
• CPC Class Codes: C08K 5/14 Peroxides
• CPC Class Codes: C08L 17/00 Compositions of reclaimed rubber
• CPC Class Codes: C08L 2205/03 containing three or more polymers in a blend
• CPC Class Codes: C08L 23/04 Homopolymers or copolymers of ethene
• CPC Class Codes: C08L 23/0853 Vinylacetate
• CPC Class Codes: C08L 23/10 Homopolymers or copolymers of propene
• CPC Class Codes: C08L 25/10 with conjugated dienes
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C08L 53/025 modified
• CPC Class Codes: C08L 9/06 : Copolymers with styrene

Abstract

The present invention relates to a crosslinkable rubber composition, the use thereof, the rubber grains formed therefrom, and a method for preparing and injection molding the rubber grains. The crosslinkable rubber composition includes at least a styrene butadiene copolymer, a softener for rubber, a flow modifier and a peroxide vulcanizing agent. The crosslinkable rubber composition is suitable for being made into rubber products. It can be made into rubber grains that will not crosslink below a temperature of 80° C. The rubber grains are formed through internal mixing, open mixing and pelleting extrusion. The rubber composition and the rubber grains of the present invention can be formed directly by injection molding and kept at room temperature over a long period of time.

Claims

1. A crosslinkable rubber composition comprising:

40-70 phr of a styrene butadiene copolymer,

10-50 phr of a softening oil for rubber,

10-30 phr of a flow modifier, and

0.1-1 phr of a peroxide vulcanizing agent.

2. The crosslinkable rubber composition according to claim 1, further includes further comprising 1-30 phr of a reclaimed material selected from the group consisting of:

reclaimed rubber, PE reclaimed materials, EVA reclaimed materials, PP reclaimed materials and combinations thereof.

3. The rubber composition according to claim 1, wherein the styrene butadiene copolymer has a molecular structure selected from the group consisting of:

a linear molecular structure and a multiple-arm star-shaped molecular structure,

wherein the molecular structure is a completely atactic copolymer structure of styrenic monomers and diene monomers or an alternating micro-block structure formed by multiple block copolymerization of styrenic monomers and diene monomers;

wherein content of a 1,2-structure in the diene monomers is 10-40% and wherein a weight percent content of the styrenic monomer in the styrene butadiene copolymer is 5-80%;

wherein a molecular formula of the styrene butadiene copolymer having the linear molecular structure is —

(PS_X—

PB_Y)_n— and

wherein the molecular formula of the styrene butadiene copolymer having the multiple-arm star-shaped molecular structure is (—

(PS_X—

PB_Y)_n)_MR, wherein —

PS is a styrenic polymer, PB is a diene polymer, R is a core of the star-shaped structure, X is a positive integer in the range of 1-300, Y is a positive integer in the range of 1-2000, n is a positive integer in the range of 10-3000, and M is a positive integer in the range of 3-20; and

,

wherein the styrene butadiene copolymer has a molecular weight of 40,000-500,000 Da.

4. The crosslinkable rubber composition according to claim 1, wherein the flow modifier is selected from the group consisting of:

styrene-butadiene-styrene copolymer, styrene-ethylene-butene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer and combinations thereof.

5. The crosslinkable rubber composition according to claim 1, wherein the softening oil for rubber is selected from the group consisting of:

naphthene oil, alkane oil, aromatic hydrocarbon oil and combinations thereof.

6. The crosslinkable rubber composition according to claim 1, wherein the vulcanizing agent is selected from the group consisting of:

benzoyl peroxide, bis(para-benzoyl peroxide), di-tert-butyl peroxide, dicumyl peroxide and cumene hydroperoxide.

7. The crosslinkable rubber composition according to claim 1, further comprising an auxiliary assistant selected from the group consisting of:

a vulcanization accelerator, an aging inhibitor, a mold releasing agent, a reinforcing agent, a flame retardant, a thickening agent, a detackifier and combinations thereof.

18. The crosslinkable rubber composition according to claim 1, wherein the rubber composition fauns a crosslinkable rubber grain.

21. The crosslinkable rubber composition according to claim 18, wherein the crosslinkable rubber grain is prepared by a method comprising the steps of:

simultaneously mixing the styrene butadiene copolymer, the flow modifier, a reclaimed material and the softening oil in an internal mixer for 10-30 minutes;

then adding the vulcanizing agent to the internal mixer and continuing mixing for 3-10 minutes at a temperature of 60-120°

C. to form a stock;

transferring the stock to and mixing the stock in an open mixer

tight-milling the stock 2-20 times;

rolling and sheeting the tight-milled stock;

extruding and pelletizing the rolled and sheeted stock using an extruder at a temperature of 60-110°

C.; and

forming the crosslinkable rubber grains by air circulation cutting or water circulation cutting the extruded and pelletized stock.

22. The crosslinkable rubber composition according to claim 18, wherein the crosslinkable rubber grain is prepared by a method comprising the steps of:

first mixing the flow modifier and the softening oil in an internal mixer for 5-15 minutes;

second, adding the styrene butadiene copolymer and a reclaimed material to the internal mixer and continuing mixing for 5-15 minutes;

third, adding the vulcanizing agent to the internal mixer and continuing internal mixing for 3-6 minutes at a temperature of 60-120°

C. to form a stock;

transferring the stock to and mixing the stock in an open mixer;

tight-milling the stock 2-20 times;

rolling and sheeting the tight-milled stock;

extruding and pelletizing the rolled and sheeted stock using an extruder at a temperature of 60-110°

C; and

forming the crosslinkable rubber grains by air circulation cutting or water circulation cutting the extruded and pelletized stock.

23. The crosslinkable rubber composition according to claim 18, wherein the crosslinkable rubber grain is prepared by a method comprising the steps of:

simultaneously mixing the styrene butadiene copolymer, the flow modifier, a reclaimed material and the softening oil in the internal mixer for 10-30 minutes at a temperature of 100-160°

C. to form a stock;

sheeting the stock after mixing;

adding the vulcanizing agent to the sheeted stock;

tight-milling the stock with the vulcanizing agent 10-20 times;

rolling and sheeting the tight-milled stock;

extruding and pelletizing the rolled and sheeted stock using an extruder at a temperature of 60-110°

C; and

forming crosslinkable rubber grains by air circulation cutting or water circulation cutting the extruded and pelletized stock.

24. A method for forming molded rubber products by injection molding the crosslinkable rubber grain according to claim 18, comprising the steps of:

heating the crosslinkable rubber grains;

pressurizing the heated crosslinkable rubber grains at a temperature of 50-120°

C. and at a pressure of 50-130 MPa to form a turbulent stock;

injecting the turbulent stock into a mold cavity; and

vulcanizing the turbulent stock in the mold cavity at a temperature of 140-190°

C. for 1-10 minutes.

25. The method of claim 24,

wherein the heating step comprises separately heating three kinds of rubber grains;

wherein the pressurizing step comprises pressurizing the three heated rubber grains having different ratios relative to each other into three separate turbulent stocks;

wherein the injecting step comprises injecting the three turbulent stocks into three noncommunicating mold cavities, respectively and

removing a middle moldboard among the three mold cavities while two other moldboards positioned at both sides of the middle moldboard are buckled back, enabling two of the three mold cavities to communicate with a third mold cavity to form an integral, interconnected mold cavity; and

wherein the vulcanizing step comprises vulcanizing the turbulent stock in the mold cavities at a temperature of 140-190°

C. and a for 100-360 s.

8. (canceled)

9. A rubber product, wherein the rubber product is made from a crosslinkable rubber composition comprising:

40-70 phr of a styrene butadiene copolymer,

10-50 phr of a softening oil for rubber,

10-30 phr of a flow modifier, and

0.1-1 phr of a peroxide vulcanizing agent.

10. The rubber product according to claim 9, wherein the rubber product is selected from the group consisting of:

raincoats, shoes, gloves, a rubber vibration isolator for automobiles, a rubber vibration isolator for railroads, a rubber vibration isolator for industrial devices, an earthquake resisting rubber for buildings and a medical apparatus.

12. The rubber product according to claim 10, wherein the rubber product is the rubber vibration isolator for automobiles selected from the group consisting of:

an engine mounting pad, a liquid seal engine bearing mounting pad, a pulley absorber, a chain wheel absorber, a carburetor mounting pad, a torsional vibration damper, a strut mounting pad, a rubber bush, a snubber rubber, an auxiliary rubber, a spring piece, a shock damper, an air spring, an automobile body mounting pad, a bumper guard, a muffler support, a rubber coupling, a central bearing support, a rubber clutch pad, a muffler mounting pad, a suspension bush,a sliding bush, a cushion for strut bar, a rubber vibration isolator for a brake, a rubber vibration isolator for a handbrake, a heat radiator support, and a muffler hanger.

13. The rubber product according to claim 10, wherein the rubber product is the rubber vibration isolator for railroads and is selected from the group consisting of a pavement pad, a ballast pad and a rail pad.

14. The rubber product according to claim 10,

wherein the rubber product is the rubber vibration isolator for industrial devices and is selected from the group consisting of:

an expansion joint, a flexible joint, a sleeve and a mounting pad.

15. The rubber product according to claim 9,

wherein the rubber product is an automobile sealing strip.

16. The rubber product according to claim 15, wherein the automobile sealing strip is selected from the group consisting of:

a car door sealing strip, a back door sealing strip, a trunk sealing strip, a side sealing strip on top, a sliding door sealing strip, a duct sealing strip, a sliding circular panel sealing strip, a front window sealing strip, a rear window sealing strip, a quarter window sealing strip, a pillar sealing strip, an outside door glass sealing strip, an inside door glass sealing strip, sealing strip for a windshield, a glass sliding track, an outside rear view mirror support, sealing strip for a closed headlight and sealing strip for a closed front upper panel.

11. (canceled)

17. (canceled)

19-20. -20. (canceled)

26-29. -29. (canceled)