High strength heat resistant rubber composition and process for producing high strength heat resistant rubber product

Abstract

According to the invention, a high strength heat resistant rubber composition having both excellent strength and heat resistance, comprising: 80 to 85 parts by mass of a rubber base material; 5 to 11 parts by mass of attapulgite; 40 to 50 parts by mass of a linear low-density polyethylene; 4 to 6 parts by mass of a ceramic powder; 2 to 6 parts by mass of a cross-linking agent; 5 to 9 parts by mass of a filler; 5 to 9 parts by mass of a cross-linking aid; 8 to 13 parts by mass of rosin; 12 to 16 parts by mass of bismaleimide; and 7 to 12 parts by mass of yttrium oxide and a process for producing a high strength heat resistant rubber product using the composition are provided.

Claims

1. A heat resistant rubber composition, comprising: 80 to 85 parts by mass of a rubber base material; 5 to 11 parts by mass of attapulgite; 40 to 50 parts by mass of a linear low-density polyethylene; 4 to 6 parts by mass of a ceramic powder; 2 to 6 parts by mass of a cross-linking agent; 5 to 9 parts by mass of a filler; 5 to 9 parts by mass of a cross-linking aid; 8 to 13 parts by mass of rosin; 12 to 16 parts by mass of bismaleimide; and 7 to 12 parts by mass of yttrium oxide.

2. The heat resistant rubber composition according to claim 1, wherein the filler comprises; 5 to 10 parts by mass of CaSO4; 5 to 11 parts by mass of montmorillonite; 5 to 10 parts by mass of calcium silicate; 3 to 6 parts by mass of sodium stearate; 4 to 7 parts by mass of zinc oxide; and 1 to 2 parts by mass of a carbon black.

3. The heat resistant rubber composition according to claim 1, wherein the cross-linking agent is a silane coupling agent.

4. The heat resistant rubber composition according to claim 1, wherein the cross-linking aid is dicumyl peroxide (DCP).

5. The heat resistant rubber composition according to claim 1, wherein the ceramic powder comprises a waste ceramic powder and the rubber base material comprises a natural rubber.

6. The heat resistant rubber composition according to claim 1, wherein the ceramic powder has an average particle diameter (D50) of 10 to 120 μm.

7. A process for producing a heat resistant rubber composition comprising the steps of: a primary kneading step of supplying and mixing 80 to 85 parts by mass of a rubber base material, 5 to 11 parts by mass of attapulgite, 40 to 50 parts by mass of a linear low-density polyethylene and 4 to 6 parts by mass of a ceramic powder in a mixer to obtain a primary kneaded product by primary kneading; a secondary kneading step of mixing 2 to 6 parts by mass of a cross-linking agent, 5 to 9 parts by mass of a filler, 5 to 9 parts by mass of a cross-linking aid, 8 to 13 parts by mass of rosin, 12 to 16 parts by mass of bismaleimide and 7 to 12 parts by mass of yttrium oxide into the primary kneaded product to obtain a heat resistant rubber kneaded product; and a forming step of forming the heat resistant rubber kneaded product obtained in the secondary kneading step to obtain a rubber product.

8. The process according to claim 7, wherein the filler comprises; 5 to 10 parts by mass of CaSO4; 5 to 11 parts by mass of montmorillonite; 5 to 10 parts by mass of calcium silicate; 3 to 6 parts by mass of sodium stearate; 4 to 7 parts by mass of zinc oxide; and 1 to 2 parts by mass of a carbon black.

9. The process according to claim 7, wherein the cross-linking agent is a silane coupling agent.

10. The process according to claim 7, wherein the cross-linking aid is dicumyl peroxide (DCP).

11. The process according to claim 7, wherein the ceramic powder comprises a waste ceramic powder and the rubber base material comprises a natural rubber.

12. The process according to claim 7, wherein the ceramic powder has an average particle diameter (D50) of 10 to 120 μm.

Description

EXAMPLES

(1) Hereinafter, the present invention will be described by way of examples but the present invention is not limited to the description of the examples below.

Example 1

(2) The high-strength heat-resistant rubber composition of the example includes, in terms of parts by mass, 80 parts of a natural rubber; 5 parts of attapulgite; 40 parts of a linear low-density polyethylene; 4 parts of a waste ceramic powder; 2 parts of a cross-linking agent; 5 parts of a filler; 5 parts of a cross-linking aid; 8 parts of a rosin; 12 parts of bismaleimide; and 7 parts of yttrium oxide.

(3) Further, the filler includes, in terms of parts by mass, 5 parts of CaSO.sub.4, 5 parts of montmorillonite; 5 parts of calcium silicate; 3 parts of sodium stearate; 4 parts of zinc oxide; and 1 part of a carbon black.

(4) The cross-linking agent is a silane coupling agent, especially silane coupling agent KH550. Polyamide-650 can also be used as the silane coupling agent.

(5) The crosslinking aid is DCP.

(6) In the example, a rubber product was manufactured by the following steps 1 to 3.

(7) Step 1: a primary kneading step of supplying and mixing the defined above parts by mass of a natural rubber, a waste ceramic powder, attapulgite and a linear low-density polyethylene in an internal mixer to obtain a primary kneaded product by primary kneading for 2 hours at 60° C.;

(8) Step 2: a secondary kneading step of mixing the defined above parts of a cross-linking agent, a filler, a cross-linking aid, a rosin, bismaleimide and yttrium oxide into the primary kneaded product to obtain a heat resistant rubber kneaded liquid by secondary kneading for 2 hours at 120° C.; and

(9) Step 3: a forming step of forming a heat resistant rubber product from the heat resistant rubber kneaded liquid obtained in the secondary kneading step to obtain a rubber product by a rubber product molding method.

(10) An injection molding method was used as the rubber product molding method.

Example 2

(11) The high-strength heat-resistant rubber composition of the example includes, in terms of parts by mass, 83 parts of a natural rubber; 8 parts of attapulgite; 45 parts of a linear low-density polyethylene; 5 parts of a waste ceramic powder; 4 parts of a cross-linking agent; 7 parts of a filler; 7 parts of a cross-linking aid; 8 parts of a rosin; 14 parts of bismaleimide; and 10 parts of yttrium oxide.

(12) Further, the filler includes, in terms of parts by mass, 8 parts of CaSO.sub.4; 8 parts of montmorillonite; 8 parts of calcium silicate; 4 parts of sodium stearate; 5 parts of zinc oxide; and 2 parts of a carbon black.

(13) The cross-linking agent is a silane coupling agent, especially silane coupling agent KH550. Polyamide-650 can also be used as the silane coupling agent.

(14) The crosslinking aid is DCP.

(15) In the example, a rubber product was manufactured by the following steps 1 to 3.

(16) Step 1: a primary kneading step of supplying and mixing the defined above parts by mass of a natural rubber, a waste ceramic powder, attapulgite and a linear low-density polyethylene in an internal mixer to obtain a primary kneaded product by primary kneading for 3 hours at 70° C.;

(17) Step 2: a secondary kneading step of mixing the defined above parts of a cross-linking agent, a filler, a cross-linking aid, a rosin, bismaleimide and yttrium oxide into the primary kneaded product to obtain a heat resistant rubber kneaded liquid by secondary kneading for 3 hours at 130° C.; and

(18) Step 3: a forming step of forming a heat resistant rubber product from the heat resistant rubber kneaded liquid obtained in the secondary kneading step to obtain a rubber product by a rubber product molding method.

(19) A press molding method was used as the rubber product molding method.

Example 3

(20) The high-strength heat-resistant rubber composition of the example includes, in terms of parts by mass, 85 parts of a natural rubber; 11 parts of attapulgite; 50 parts of a linear low-density polyethylene; 6 parts of a waste ceramic powder; 6 parts of a cross-linking agent; 9 parts of a filler; 9 parts of a cross-linking aid; 13 parts of a rosin; 16 parts of bismaleimide; and 12 parts of yttrium oxide.

(21) Further, the filler includes, in terms of parts by mass, 10 parts of CaSO.sub.4; 11 parts of montmorillonite; 10 parts of calcium silicate; 6 parts of sodium stearate; 7 parts of zinc oxide; and 2 parts of a carbon black.

(22) The cross-linking agent is a silane coupling agent, especially silane coupling agent KH550. Polyamide-650 can also be used as the silane coupling agent.

(23) The crosslinking aid is DCP.

(24) In the example, a rubber product was manufactured by the following steps 1 to 3.

(25) Step 1: a primary kneading step of supplying and mixing the defined above parts by mass of a natural rubber, a waste ceramic powder, attapulgite and a linear low-density polyethylene in an internal mixer to obtain a primary kneaded product by primary kneading for 2.5 hours at 75° C.;

(26) Step 2: a secondary kneading step of mixing the defined above parts of a cross-linking agent, a filler, a cross-linking aid, a rosin, bismaleimide and yttrium oxide into the primary kneaded product to obtain a heat resistant rubber kneaded liquid by secondary kneading for 2.5 hours at 120° C.; and

(27) Step 3: a forming step of forming a heat resistant rubber product from the heat resistant rubber kneaded liquid obtained in the secondary kneading step to obtain a rubber product by a rubber product molding method.

(28) A wrap forming method was used as the rubber product molding method.

(29) The rubber product molding method according to the present invention is not limited to the methods used in Examples 1 to 3 described above, and any conventionally known rubber molding method such as a transfer molding method can be used.

(30) The high-strength heat-resistant rubber products obtained thus above were evaluated. The results of evaluation are shown in Table 1 below.

(31) It should be noted that the density was measured by using the measuring method B of the sulfurized rubber or the thermoplastic rubber density of GB/T533-2008.

(32) The hardness test was carried out by using the Shore hardness method which is Part I of the GB/T5331.1-2008 vulcanized rubber or thermosetting rubber indentation hardness test method.

(33) TABLE-US-00001 TABLE 1 Results of evaluation of characteristic each of high strength and heat resistant rubber according to the invention Measurement Measurement Item Standard Example 1 Example 2 Example 3 Density GB/T 533-2008 1.210 1.212 1.212 Shore hardness GB/T 5331.1-2008 51 52 52 Elongation at GB/T 528-2009 620 619 620 break point (%) Permanent GB/T 528-2009 20 21 21 strain (%) Heat resistant HG/T 3847-2008 300 300 300 temperature

(34) As can be understood from Table 1, the high strength heat resistant rubber product according to the invention has a high density, a sufficiently high strength, excellent elasticity, elongation at break and permanent strain and also has excellent heat resistance as achieving heat resistant temperature up to 300° C.

(35) As will be appreciated by those skilled in the art, the invention is not limited by the description of the above embodiments. The above examples and specification are merely for explaining the principle of the invention. Various modifications and improvements can be made without departing from the spirit and scope of the invention. All such modifications and improvements are included in the scope of the invention as claimed. Further, the scope of protection as claimed in the claims includes not only the scope of the claims but also equivalents thereof.