JP2703047B2 - Chlorinated polyethylene composition - Google Patents

Description

The present invention relates to a chlorinated polyethylene composition having good permeation resistance to freon gas, and particularly excellent in mechanical strength (for example, tensile strength, tear strength). And a chlorinated polyethylene composition having excellent oil resistance.

[Prior Art] As is well known, freon gas is widely used as a refrigerant gas for air conditioners, refrigerators, freezers and the like. This type of freon gas has a greater cooling effect as the molecular weight decreases. However, it is well known that R-12 is usually used because the gas permeability increases as the molecular weight decreases. Acrylonitrile-butadiene copolymer rubber (hereinafter referred to as “NBR”) is used for freon gas hoses, tubes, and packings used in the automobile industry, industrial parts industry, and home appliance industry. A problem that the ozone layer in the atmosphere, which is beginning to become a global problem, is destroyed by freon gas, and resins and rubbers that can withstand freon gas have been demanded in the industry.

As a generally used freon gas hose, NBR is used as an inner layer as a rubber capable of withstanding R-12, and chloroprene rubber (CR) or acrylic rubber is used as an outer layer.

[Problem to be Solved by the Invention] A hose manufactured from the above-mentioned NBR and chloroprene rubber or acrylic rubber, having a molecular weight of 80 to 115 and a boiling point (1 atm) of -30 ° C or less, which is satisfactory to Freon gas There is a problem that the light cannot pass through and is transmitted.

From the above, the present invention does not have these disadvantages (problems), that is, it has good permeation resistance to freon gas,
A rubber composition (chlorinated polyethylene composition) that has excellent heat resistance, good oil resistance and mechanical strength, and excellent temperature resistance and stretch resistance (very low freon gas transmission). It is to get.

[Means and Actions for Solving the Problems] According to the present invention, these problems include (A) chlorinated polyethylene, (B) a polyamide resin that melts at 210 ° C., and (C) a melt index of [JIS]. According to K7210, measured under condition 4, hereinafter referred to as "MI (1)"] is 0.1
200200 g / 10 min, and the copolymerization ratio of α, β-unsaturated dicarboxylic acid and its anhydride is 0.5 to 25 in total.
Mol% of chlorinated ethylene copolymer of at least ethylene and α, β-unsaturated dicarboxylic acid and / or anhydride thereof, wherein the chlorine content of the chlorinated product is 5 to 5.
A chlorinated ethylene copolymer having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 5 or more, wherein the composition ratio of chlorinated polyethylene in the total amount is 10 to A chlorinated polyethylene composition, wherein the composition ratio of the polyamide resin is 65% by weight and the composition ratio of the polyamide resin is 5.0 to 40% by weight, but the composition ratio of the chlorinated product of the ethylene copolymer is at least 20% by weight. Can be. Hereinafter, the present invention will be described in more detail.

(A) Chlorinated polyethylene Chlorinated polyethylene used in the present invention is obtained by chlorinating polyethylene powder or particles in an aqueous suspension or chlorinating polyethylene dissolved in an organic solvent. Yes (preferably obtained by chlorination in aqueous suspension). Generally, it is an amorphous chlorinated polyethylene having a chlorine content of 25 to 45% by weight, particularly preferably an amorphous chlorinated polyethylene having a chlorine content of 27 to 45% by weight.

The polyethylene is obtained by homopolymerizing ethylene or copolymerizing ethylene with at most 20% by weight of an α-olefin (generally, having at most 12 carbon atoms). Its density is generally 0.910-0.970g /
cc. Also, its molecular weight is at least 30,000,
Particularly, 50,000 to 700,000 is preferable.

Mooney viscosity of this chlorinated polyethylene (ML _{1 +} 4,100
C) is usually from 20 to 100, and particularly preferably from 25 to 90.

(B) Polyamide resin The polyamide resin used in the present invention comprises 21
It melts at a temperature of 0 ° C. 210 ° C
If a polyamide resin that does not melt at the temperature of the above is used, kneading to produce the composition at a temperature at which the polyamide resin melts, or attempting to mold the composition, the chlorinated polyethylene in the composition becomes hot. Decompose. On the other hand, when chlorinated polyethylene attempts to knead or mold by thermal decomposition, the polyamide resin does not melt.

The polyamide resin generally has a heat of crystal fusion measured by a differential scanning calorimeter of less than 2 cal / g. Heat of crystal fusion is 2c
If it exceeds al / g, the melting point of the amide resin is high.

The polyamide resin, as an acid, adipic acid, sebacic acid, ω-aminoundecanoic acid, ω-aminododecanoic acid, azelaic acid, terephthalic acid, isophthalic acid, cyclohexane-1,4-dicarboxylic acid, etc. , 6-Hexamethylenediamine, trimethyl-1,6-
Hexamethylenediamine, 4,4'-diamino-dicyclohexylenemethane, 4,4'-diamino-3,3'-dimethyldicyclo-hexylenemethane, 4,4'-diamino-dicyclohexylenepropane, isophoronediamine , And lactams, caprolactam, laurolactam, ω
-Laurolactam, and further as isocyanate, 4,
It is obtained by polycondensing 4'-diphenylmethane diisocyanate and tolylene diisocyanate.
This polyamide resin is produced by subjecting these polycondensation components to melt polymerization and solution polymerization, respectively. The solution polymerization method is basically a pressure melt polymerization method as in the production of ordinary nylon-6 or nylon 66, but in the case of the polyamide resin, an aromatic dicarboxylic acid may be used as a raw material dicarboxylic acid. In addition, since the polymerization temperature is relatively high, there is a problem that the polymer produced during melt polymerization tends to be colored or gelled. Therefore, various kinds of methods such as adding a phosphorus-based compound during polymerization to prevent coloring and gelling, and performing a two-stage polymerization consisting of a pre-condensation step and a post-condensation step using terephthalic acid diester as a starting material, and the like. It is desirable to devise.

Further, as the solution polymerization method, a decarboxylation condensation reaction between diisocyanate and dicarboxylic acid may be used.

(C) Chlorinated ethylene-based copolymer Further, in producing the chlorinated ethylene-based copolymer used in the present invention, the raw material ethylene-based copolymer is at least ethylene and “α, β-unsaturated dicarboxylic acid”. Acid and / or anhydride thereof [hereinafter, referred to as “comonomer (1)”). The copolymer may be a copolymer of ethylene and the comonomer (1). In addition to the ethylene and the comonomer (1), the copolymer comprises “an unsaturated carboxylic acid ester, an alkoxyalkyl acrylate and a vinyl ester” as a third copolymer component. Monomers with at least one double bond selected from the group "
[Hereinafter referred to as “comonomer (2)”].

 Among the comonomers (1), α, β-unsaturated dicarboxylic acids
The acid usually has at most 20 carbon atoms, especially 4 to 16 carbon atoms.
Individuals are preferred. As a representative example of the dicarboxylic acid
Is maleic acid, fumaric acid, itaconic acid, citracone
Acid, 3,6-endomethylene-1,2,3,6-tetrahydro-cy
Su-phthalic acid (nadic acid ).

Among the α, β-unsaturated dicarboxylic acid components of the present application, anhydrides of the α, β-unsaturated dicarboxylic acids are desirable, and among them, maleic anhydride is preferably an acid.

Among the comonomers (2), the unsaturated carboxylic acid ester usually has 4 to 40 carbon atoms, and particularly preferably 4 to 20 carbon atoms. As a typical example, those having good heat stability such as methyl (meth) acrylate and ethyl (meth) acrylate are preferable, and those having poor heat stability such as t-butyl (meth) acrylate cause foaming and the like, and thus are preferable. Absent.

Furthermore, the alkoxyalkyl acrylate usually has at most 20 carbon atoms. The alkyl group preferably has 1 to 8 (preferably 1 to 4) carbon atoms, and the alkoxy group has 1 to 8 carbon atoms (preferably 1 to 4 carbon atoms).
4) are desirable. Representative examples of preferred alkoxyalkyl acrylates include methoxyethyl acrylate, ethoxyethyl acrylate, and butoxyethyl acrylate.

Also, the carbon number of vinyl ester is generally at most
There are 20 (preferably 4 to 16). Representative examples of suitable vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl bivalate, and the like.

In the ethylene copolymer of the present invention, the copolymerization ratio of the comonomer (1) is 0.5 to 25 mol%, preferably 1.0 to 25 mol%, and particularly preferably 1.0 to 20 mol%. When an ethylene-based copolymer having a copolymerization ratio of the comonomer (1) of less than 0.1 mol% is used, the effect of the obtained chlorinated product is not exhibited. On the other hand, an ethylene copolymer exceeding 25 mol% has problems in cost and production when industrially produced.

In the present invention, the terpolymer composed of ethylene, comonomer (1) and comonomer (2) has no blocking during chlorination, and the reaction can be easily carried out. Further, the obtained chlorinated ethylene copolymer is preferable because of excellent rubber elasticity and heat resistance.

Further, the copolymer ratio of the comonomer (2) is generally at most 25 mol% in terms of production and cost, and
5 to 25 mol% is desirable, especially 1.0 to 25 mol%
Are preferred.

The MI (1) of the ethylene copolymer is 0.1 to 100 g / 10 minutes, preferably 0.5 to 100 g / 10 minutes, and more preferably 1.0 to 100 g / 10 minutes.
g / 10 minutes are preferred. If an ethylene copolymer having an MI (1) of less than 0.1 g / 10 minutes is used, the moldability and kneading properties of the resulting chlorinated ethylene copolymer are not good. on the other hand,
If an ethylene-based copolymer exceeding 100 g / 10 minutes is used, the resulting chlorinated ethylene-based copolymer has poor mechanical properties.

To produce the chlorinated ethylene copolymer of the present invention,
The ethylene-based copolymer is suspended in an aqueous medium. In order to maintain this aqueous suspension, it is preferable to add a small amount of an emulsifier and a suspending agent. At this time, if necessary, a radical generator such as benzoyl peroxide, azobisisobutyronitrile and hydrogen peroxide, a defoaming agent such as light silicone oil, and other additives may be added.

In producing the chlorinated ethylene copolymer of the present invention, it is desirable to chlorinate the above aqueous suspension by the following three methods.

The first method is at least 25 ° C. lower than the melting point of the ethylene copolymer used in the first step, but chlorinates 20 to 60% of the total chlorinated amount at a temperature higher than 50 ° C., In this method, the remaining chlorination is carried out at a temperature which is at least 10 ° C. higher than the chlorination temperature in the first step but lower than the melting point of the ethylene-based copolymer by 5 to 15 ° C.

In the second method, the temperature is at least 25 ° C. lower than the melting point of the ethylene copolymer used in the first step, but the total chlorination amount is 20 to 60 at a temperature higher than 50 ° C.
%, And in a second step, the temperature is raised to a temperature 1 to 7 ° C. higher than the melting point of the ethylene-based copolymer, and at this temperature, annealing is performed for 10 to 60 minutes without introducing chlorine, and in a third step, This is a method in which the remaining chlorination is carried out at a temperature 2 to 25 ° C. lower than the melting point of the ethylene copolymer.

Furthermore, the third method is a temperature at least 25 ° C. lower than the melting point of the ethylene copolymer used in the first step, but even at a temperature higher than 50 ° C., the total chlorination amount is 20%.
Chlorination of about 60%, and in the second step the temperature is 10 ° C. or more higher than the chlorination temperature in the first step, but the remaining chlorine is 5 to 15 ° C. lower than the melting point of the ethylene copolymer. At least 30% of the total amount of chlorination by this stage, and then in a third stage at a temperature lower than the melting point of the ethylene-based copolymer,
In this method, chlorination is performed at a temperature lower than the melting point by 2 ° C. or less.

The chlorine content of the chlorinated ethylene copolymer used in the present invention thus obtained is 5 to 45% by weight.
(Preferably 5 to 40% by weight, suitably 10 to 35% by weight). If the chlorine content of the chlorinated ethylene copolymer is less than 5% by weight, there is a problem in recovering and purifying the obtained chlorinated ethylene copolymer. Moreover, the flame resistance is poor. On the other hand, when the content exceeds 45% by weight, a chlorinated ethylene-based copolymer produced is not preferred because the thermal stability and heat resistance are significantly reduced.

The Mooney viscosity of the large rotor at a temperature of 100 ° C. is 5 points or more, preferably 5 to 150 points, and more preferably 10 to 150 points.

Further, the melt index (measured under the condition of 8 according to JIS K-7210, hereinafter referred to as "MI (2)") is generally 1 to 100 g / 10 minutes, preferably 3 to 50 g / 10 minutes, Particularly, 5 to 30 g / 10 minutes is preferable.

(D) Composition ratio The composition ratio of the chlorinated polyethylene in the chlorinated polyethylene composition of the present invention is 10 to 65% by weight, and 12 to 65% by weight.
Is preferred, and particularly preferably 15 to 65% by weight. If the composition ratio of chlorinated polyethylene in the composition is less than 10% by weight,
Poor flexibility and poor mechanical properties of the composition.
On the other hand, when the content exceeds 65% by weight, the composition has good flexibility but cannot obtain a composition having balanced mechanical properties.

The composition ratio of the polyamide resin is 5.0 to 40% by weight, preferably 5.0 to 38% by weight, and particularly preferably 5.0 to 35% by weight. If the composition ratio of the polyamide resin in the composition is less than 5.0% by weight, a composition having balanced mechanical properties cannot be obtained. On the other hand, if it exceeds 40% by weight, the composition has excellent mechanical properties, but cannot have a high flexural modulus (rigidity) and good flexibility.

However, the composition ratio of the chlorinated product of the ethylene copolymer in the composition is at least 20% by weight,
% By weight or more, and particularly preferably 25% by weight or more. If the composition ratio of the chlorinated ethylene copolymer in the composition is less than 20% by weight, the obtained composition has poor flexibility and processability.

(E) Mixing method, molding method, etc. Although the composition of the present invention can be obtained by uniformly blending the above substances, fillers, plasticizers, oxygen generally used in the rubber and resin industries can be obtained. , Ozone, heat and light (ultraviolet) stabilizers, organic peroxides (as crosslinking agents), crosslinking accelerators, tackifiers, plasticizers, shuffling agents, curing agents, slip agents, flame retardants, charging Additives such as inhibitors, lubricants and colorants may be added according to the intended use of the composition.

In producing the composition of the present invention, the compounding (mixing) method may be performed by using a mixer generally used in the technical field such as an open roll, a drive render, a Banbury mixer and a kneader. Among these mixing methods, in order to obtain a more uniform composition, two or more of these mixing methods may be applied (for example, after mixing by a drive render in advance, the mixture is mixed using an open roll). how to).

The composition of the present invention may be formed into a desired shape by using a molding machine such as an extrusion molding machine, an injection molding machine, a compression molding machine and a stamping molding machine which are usually used in the general rubber industry. In addition, in the rubber technical field, a method of manufacturing a molded product while generally vulcanizing (crosslinking) by adding chlorinated polyethylene or the above-described composition, that is, a method of simultaneously performing vulcanization and molding is applied. It may be formed into a desired shape.

[Examples and Comparative Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.

In Examples and Comparative Examples, tensile strength (hereinafter, referred to as “T _B ”) and elongation (hereinafter, referred to as “E _B ”) are AS
Measured using a Tensilon tester according to TM D790. The flexural modulus was measured using a Tensilon tester according to ASTM D790. Further, the gas permeability was determined from the change in weight after standing at 1 atm and a temperature of 80 ° C. for 24 hours using Freon 22 as a gas of a fluorine-based organic compound according to ASTM D1434.

The physical properties and types of chlorinated polyethylene, EVOH (a saponified product of ethylene-vinyl acetate copolymer), polyamide resin, inorganic filler and other additives used in Examples and Comparative Examples are shown below.

[(A) Chlorinated polyethylene] As chlorinated polyethylene, chlorinated polyethylene obtained by chlorinating polyethylene (average molecular weight: about 100,000) having a density of 0.930 g / cm ³ by an aqueous suspension method [containing chlorine 43.0% by weight, amorphous, hereinafter referred to as [CPE].

[(B) Polyamide resin] Further, the polyamide resin has a melting point of 169 ° C,
A condensation polymer of ω-aminoundecane having a density of 1.0 g / cm ³ (hereinafter referred to as “PA”) was used.

[(C) Chlorinated ethylene copolymer] Further, as a chlorinated ethylene copolymer, MI (1)
Is 100 g / 10 minutes ethylene-methyl methacrylate-
Maleic anhydride terpolymer (copolymerization ratio of methyl methacrylate 18.5 mol%, copolymerization ratio of maleic anhydride
Chlorinated product obtained by chlorinating 1.9 mol%) by an aqueous suspension method (chlorine content 35.1% by weight, Mooney viscosity (ML _{1 + 4} , 100 ° C) 28, hereinafter referred to as “Cl-ET”) It was used.

[(D) Inorganic Filler] Furnace black (manufactured by Showa Cabot Co., trade name, Show Black SRF, average particle size 72 nm, hereinafter referred to as "SRF") was used as the inorganic filler.

[(E) Other additives] Further, as other additives, magnesium oxide [Kyowa Mag # 150, 100, manufactured by Kyowa Chemical Industry Co., Ltd.]
Mesh pass, specific surface area 150m ² / g, hereinafter referred to as “MgO”)
As a stabilizer, a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline (hereinafter referred to as `` 2,2,4 '') as an antioxidant, and chlorinated paraffin (hereinafter referred to as `` salt '') as a plasticizer. Para "
Was used. Also, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane (hereinafter referred to as "peroxide") as a cross-linking agent, and triallyl isocyanate (hereinafter referred to as "TAIC") as a cross-linking aid. 〕It was used.

Examples 1 to 5, Comparative Examples 1 to 9 Chlorinated polyethylene (CPE), polyamide resin (PA), chlorinated ethylene-based copolymer (Cl-ET), the amounts of which are shown in Table 1 respectively, The inorganic filler, stabilizer, antioxidant and plasticizer were sufficiently kneaded for 20 minutes using an open roll whose surface temperature was previously set to 170 ° C. Next, the surface temperature was set to 150 ° C., a crosslinking agent and a crosslinking assistant were further added, and the mixture was further kneaded for 10 minutes to form a sheet. The temperature of the obtained sheet is 185 ° C,
It was hot-pressed for 15 minutes under the condition of a pressure of 200 kg / cm ² to prepare crosslinked sheets. The tensile strength, elongation, and gas permeability of each sheet thus obtained were measured.
Table 2 shows the results.

From the results shown in Table 2, it is clear that the chlorinated polyethylene composition of the present invention has excellent flexibility and permeability to fluorine-based refrigerant gas.

[Effect of the Invention] The chlorinated polyethylene composition of the present invention exhibits the following effects (features).

(1) Good mechanical strength.

(2) Excellent heat resistance.

(3) Good stress cracking properties (metal degradation).

(4) Excellent tearability.

(5) Good oil resistance.

(6) Excellent compression set.

The chlorinated polyethylene composition of the present invention can be used in various fields to exhibit the above effects. Representative applications are shown below.

(1) Various automotive parts such as hoses for freon gas, puncturing, sealing materials, etc. (2) Various home appliance parts such as puncturing and sealing materials.

Claims (1)

(57) [Claims] (A) a chlorinated polyethylene, (B) a polyamide resin melting at 210 ° C., and (C) a melt index of 0.1 to 100 g / 10 minutes,
And ethylene and α, β-unsaturated dicarboxylic acid and / or anhydride having a total copolymerization ratio of 0.5 to 25 mol% of α, β-unsaturated dicarboxylic acid and its anhydride.
Or a chlorinated product of an ethylene copolymer with an anhydride thereof, wherein the chlorinated product has a chlorine content of 5 to 40% by weight;
And a chlorinated ethylene copolymer having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 5 or more, wherein the composition ratio of chlorinated polyethylene in the total amount thereof is 10 to 65% by weight, A chlorinated polyethylene composition wherein the composition ratio of the polyamide resin is 5.0 to 40% by weight, and the composition ratio of the chlorinated ethylene copolymer is at least 20% by weight.