JPS61188440A - Vinyl chloride resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. having excellent compression set, mechanical strength, moldability and flow characteristics, consisting mainly of a vinyl chloride resin, a rubbery copolymer and a plasticizer. CONSTITUTION:100pts.wt. vinyl chloride resin (A) having an average degree of polymn. of 400-10,000, 20-200pts.wt. rubbery copolymer (B) which has a tetrahydrofuran-insolubles content of 50wt% or above, in which said insolubles have a Q valve of 20 or below represented by the formula (wherein W is the weight in g of a solvent-contg. swollen rubbery copolymer obtd. by accurately weighing about 1g of said insolubles of component B, immersing it in tetrahydrofuran and allowing it to stand in said solvent at 25 deg.C for 24hr; W' is the dry weight in g of said swollen rubbery copolymer) and which has a Mooney viscosity (ML1+4, 100 deg.C) of 10-40 and is composed of 55-80wt% conjugated diene (e.g. butadiene), 20-45wt% alpha,beta-unsaturated nitrile (e.g. acrylonitrile) and 0-10wt% other copolymerizable monomer (e.g. divinylbenzene), and 0-200 pts.wt. plasticizer (c) are blended together.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application □ The present invention relates to a vinyl chloride resin composition that has excellent compression set characteristics, mechanical strength, and moldability.

Conventional technology □ In general, vinyl chloride resin is made into a soft vinyl chloride resin that has moderate elasticity and flexibility by adding a plasticizer to the resin, and is used in various molding materials. There is.

However, such soft vinyl chloride molded products have poor creep resistance (compression set characteristics) and have a smaller restoring force after stress is applied than rubber, and are used in applications such as packing that require compression set characteristics. could not be used for

On the other hand, as a method to improve the compression set characteristics of vinyl chloride resin, using vinyl chloride resin with a high degree of polymerization,
Alternatively, it is known to use a crosslinked vinyl chloride resin, but such a vinyl chloride resin has significantly reduced moldability and is not practically suitable for mass production.

Problems to be Solved by the Invention In recent years, compositions in which an appropriate amount of gel-containing nitrile rubber having an insoluble portion in a solvent such as methyl ethyl ketone is mixed have been proposed in order to improve creep resistance and shape retention at high temperatures. (Unexamined Japanese Patent Publication No. 56-115342, No. 57-1
87341).

However, in a vinyl chloride resin composition, even if the mixing amount of nitrile rubber, which merely contains a gel component as described above, is increased for the purpose of improving compression set characteristics, the fluidity deteriorates, and problems arise during extrusion molding. This causes a problem that the extrusion rate decreases and injection molding is difficult. For this reason,
Increasing the amount of plasticizer blended for the purpose of increasing fluidity improves moldability, but leads to a decrease in mechanical properties.

The purpose of the present invention is to have excellent compression set characteristics, fluidity,
Another object of the present invention is to provide a vinyl chloride resin composition that also has excellent mechanical properties.

Means for Solving the Problems As a result of intensive studies against the background of such conventional technical problems, the present inventors have developed a rubber-like polyvinyl chloride resin that has specific crosslinking properties and has a specific molecular weight. The present invention was achieved by discovering that the above object can be achieved by blending an appropriate amount of a copolymer.

That is, the present invention provides (55 to 80% by weight α of (bll conjugate upper F) to 100 parts by weight of (al vinyl chloride resin).

β-unsaturated nitrile 20~. A rubbery copolymer consisting of 45% by weight and 0 to 10% by weight of other copolymerizable heptamers, the insoluble content in tetrahydrofuran is 50% by weight or more, and the following Q value of the tetrahydrofuran insoluble content is 20 and the Mooney viscosity (M
20 to 200 parts by weight of a rubbery copolymer having an L l -a , 100°C) of 10-40, and (C) 0 to 200 parts by weight of a plasticizer. , provides a nil-based resin composition.

W' W: About 1 g of accurately weighed rubbery copolymer was immersed in 100 ml of tetrahydrofuran as a solvent, left to stand for 624 hours, and then gently poured onto a wire mesh of 200 mesh to collect insoluble matter. The weight (g) of the gel (swollen rubbery copolymer) swollen with tetrahydrofuran obtained by removing the tetrahydrofuran attached to the surroundings with a filter paper and immediately weighing it accurately W'; Dry weight (g) of the copolymer obtained by vacuum drying at 60°C for 12 hours The vinyl chloride resin (a) used in the present invention is usually
A commonly used vinyl chloride resin may be used, and the average degree of polymerization is 400 to 10,000, preferably 1.000 in consideration of processability, mechanical strength, and the balance between the two.
~3.000 are used.

In addition, such vinyl chloride resin is a copolymer with other copolymerizable monomers such as styrene, acrylonitrile, alkyl vinyl ether, acrylic acid alkyl ester, fatty acid vinyl ester, methacrylic acid alkyl ester, and vinylidene halide. It may be.

Next, the BL rubbery copolymer used in the present invention is composed of the specific monomer components as described above, and has specific gel behavior (insoluble content in tetrahydrofuran of 50% by weight or more, Q value of 20 or less). ), and the Mooney viscosity is limited.

That is, the conjugated diene constituting the rubber-like copolymer (b) may include butadiene, isoprene, preferably butadiene, and the content of these conjugated dienes in the copolymer is 55 to 80% by weight. %, weight is 5
0-70% by weight, more preferably 57-65% by weight. If the conjugated diene content is less than 55% by weight, the processability of the resulting composition will deteriorate, while if it exceeds 80% by weight, the effect of improving the compression set properties of the composition will be poor, and the mechanical strength may decrease. .

Examples of the α,β-unsaturated nitrile include acrylonitrile, methacrylaterile, preferably acrylonitrile, and the content of these α,β-unsaturated nitriles in the rubbery copolymer is 20 to 45%.
% by weight, preferably 30-45% by weight, more preferably 35-43% by weight.

If the content of α,β-unsaturated nitrile is less than 20% by weight, the compatibility with vinyl chloride resin will be poor, and the processability and mechanical strength will decrease, while if it exceeds 45% by weight, it will be the object of the present invention. Poor effect on improving compression set properties.

Furthermore, other copolymerizable monomers include functional monomers and/or polyfunctional monomers.

Here, the functional monomers include (meth)acrylates, maleates, and fumarates having carboxyl groups, epoxy groups, hydroxyl groups, and amino groups, and specifically include hydroxyethyl (meth)acrylate, (meth)acrylic acid, and maleic acid. , glycidyl (meth)acrylate, diglycidyl maleate, diethylaminoethyl (meth)acrylate, and the like.

Furthermore, the polyfunctional monomer is a compound having two or more functional groups, preferably two copolymerizable double bonds, and specifically non-conjugated divinyl compounds such as divinylbenzene, divinylxylene, and divinyl ether. , polyhydric (meth)acrylate compounds such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, unsaturated compounds such as vinyl (meth)acrylate, isopropenyl (meth)acrylate, and divinyl phthalate. Examples include carboxylic acid esters.

The content of these other copolymerizable monomers in the rubbery copolymer is 0 to 10% by weight, preferably 0.5% by weight.
~5% by weight, and is added as necessary to obtain a rubbery copolymer that exhibits a specific gel behavior with respect to tetrahydrofuran, which is a characteristic of the copolymer. On the other hand, if it exceeds 10% by weight, the degree of crosslinking of the rubbery copolymer becomes too large, resulting in a decrease in the mechanical strength of the resulting composition.

[b) The rubbery copolymer used in the present invention requires the above-mentioned monomer composition, but also exhibits the following gel behavior and has a specific molecular weight indicated by Mooney viscosity. It is necessary.

That is, 1 g of the rubbery copolymer is accurately weighed and extracted with 100 ml of tetrahydrofuran at 25°C for 24 hours to extract the insoluble matter (hereinafter sometimes simply referred to as "tetrahydrofuran insoluble matter" or rTHF insoluble matter). is 50% by weight or more, preferably 70 to 95% by weight, and if it is less than 50% by weight, a composition with excellent compression set properties cannot be obtained.

Moreover, the present invention cannot be achieved simply by having a large amount of tetrahydrofuran insoluble matter, and unless the cohesive force of the insoluble matter is sufficient, the intended effects of the present invention cannot be achieved. Therefore, the rubbery copolymer (b) used in the present invention needs to have a Q value as defined above of 20 or less, preferably 3.0 to 15.0.

That is, when the Q value of the rubbery copolymer exceeds 20, the cohesive force of the tetrahydrofuran-insoluble components becomes insufficient, and even if a composition using such a copolymer is subjected to molding, the compression set cannot be improved. Also, the fluidity is poor and the moldability is poor.・It is generally known to increase the content of a gel-containing rubbery substance in order to improve the compression set of a resin composition, but increasing the amount of such a substance blended improves the compression set properties but reduces fluidity. Moreover, mechanical strength also decreases.

However, the present invention contains a gel as described above,
Moreover, by using a rubbery copolymer whose gel cohesive force is specified, it is possible to obtain a composition that has good fluidity and excellent compression set and mechanical strength.

Furthermore, in the present invention, the rubbery copolymer (b) has a Mooney viscosity (M L +, 4.100°C), which is a guideline for its molecular weight.
) is 10 to 40, preferably 15 to 35. If the Mooney viscosity of the rubbery copolymer is less than 10, although the fluidity will be good, it will not be possible to obtain a composition with excellent compression set properties, while if it exceeds 40, the fluidity of the resulting composition will decrease. This results in a significant decrease in the extrusion rate during extrusion molding, and cannot be used in injection molding, which requires a high degree of fluidity.

In general, the mechanical strength of rubber is better as the molecular weight increases, but surprisingly, in the present invention, mechanical strength is improved by using a rubbery copolymer with a relatively low Mooney viscosity as described above. A vinyl chloride resin composition with excellent properties can be obtained.

As mentioned above, the tetrahydrofuran insoluble content was 50% by weight.
or more, the cohesive force of the insoluble matter is sufficiently high, and the molecular weight indicated by Mooney viscosity is in an appropriate range (b)
By using a rubbery copolymer, a vinyl chloride resin composition with an excellent balance between compression set characteristics and fluidity can be obtained.

The amount of the rubbery copolymer (b) in the present invention is:
The amount is 10 to 200 parts by weight, preferably 30 to 150 parts by weight, per 100 parts by weight of the vinyl chloride resin.If it is less than 10 parts by weight, the effect of improving compression set properties will be poor, while if it exceeds 200 parts by weight. This will be accompanied by a decrease in moldability.

Note that the (bl rubbery copolymer can be easily produced, for example, by the method described below.

That is, the monomer mixture described above is emulsified and dispersed in an aqueous solution of an emulsifier such as an alkyl sulfate, an alkylaryl sulfonate, or a salt of a higher fatty acid, and a radical polymerization catalyst such as a persulfate or a peroxide is added as a catalyst to emulsify the mixture. Polymerized and unreacted monomers.

After removing T, the T of the present invention is coagulated and dried.
A bl rubbery copolymer can be obtained.

Next, as the plasticizer (C) used in the present invention, any plasticizer that is generally used for vinyl chloride resins may be used, such as alkyl esters of aromatic polybasic acids such as dibutyl phthalate and dioctyl phthalate. ,
Examples include alkyl esters of aliphatic polybasic acids such as dioctyl adipate and dioctyl sebacate, and phosphoric acid alkyl esters such as tricresyl phosphate.

(c) The blending amount of the plasticizer is 0 to 200 parts by weight, preferably 30 to 120 parts by weight, per 100 parts by weight of the vinyl chloride resin.
If the amount exceeds 200 parts by weight, moldability deteriorates and handling becomes difficult.

The vinyl chloride resin composition of the present invention can be used as it is, but if necessary, it can be used by adding heat stabilizers, fillers, pigments, processing aids, etc. It is also possible to add and use other thermosetting resins.

As the heat stabilizer, lead-based or tin-based heat stabilizers commonly used as stabilizers for vinyl chloride, metal soaps, and the like can be used.

For producing the vinyl chloride-based resin composition of the present invention (
a) Vinyl chloride resin, (b) rubbery copolymer and (
C) The mixing and shaping of the three components of the plasticizer may be carried out by any method provided that the respective components are substantially uniformly dispersed, mixed, and kneaded, such as in a Henschel mixer, ribbon blender, etc. Tri-blending may be performed, and the tri-blend powder may be directly molded, or it may be melt-kneaded using an extruder, rolls, etc., then pelletized, and then molded. The molding method can be selected depending on the desired product, such as extrusion molding, injection molding, blow molding, calendar molding, and vacuum molding.

The vinyl chloride resin composition of the present invention has excellent moldability, compression set characteristics, and mechanical strength.
It can be widely used for sealing materials, cushioning materials, gaskets, leather films, wire covering materials, etc.

Effects of the Invention The vinyl chloride resin composition of the present invention has an excellent balance between compression set characteristics and flow characteristics, and also has good mechanical strength.

Therefore, it can be used for various sealing materials, cushioning materials, sealing materials, etc.

Examples Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples.

In addition, in the examples, the compression set characteristics, tensile test, and flow test were conducted according to the following test methods.

(i) Compression set characteristics According to JIS K6301, 70°C x 22 hours, 25
Measured under conditions of % compression.

(ii) Tensile test according to JIS K6723, tensile speed 200 mm7
It was measured in minutes and was used as an index of mechanical strength.

(iii) Using a flow tester with a flow test nozzle diameter of 1 Φ, the melting temperature was 190°C and the load was 20 kg, and 50 kg.
g was measured and used as an index of flow characteristics and moldability.

Reference example (manufacturing example of rubber-like copolymer) Using the monomers and polymerization agents shown below, the inner volume was 201.
Radical emulsion copolymerization was carried out at 10°C in an autoclave.

(Parts by weight) Butadiene 54 Acrylonitrile 44 Divinylbenzene
2 water
220 Sodium dodecylbenzenesulfonate 3.5 Tertiary dodecyl mercaptan 1.6 Potassium persulfate 0.27 Cyanoethylated diethanolamine 0.15 Potassium hydroxide
After the 0.10 polymerization rate reached 90%, 0.2 parts by weight of hydroxylamine per 100 parts by weight of monomer was added to stop the polymerization.

Next, after steam distilling this polymerization product liquid to remove residual monomers, 2 parts by weight of nalkylated phenol was added as an anti-aging agent per 100 parts by weight of copolymer solid content,
The latex was coagulated with an aqueous calcium chloride solution. After washing the obtained coagulated material with water, it was dried at 50° C. under reduced pressure to obtain a sample A for evaluation.

Samples B to L were obtained using the same recipe by changing the amount of Ti and the amount of tertiary dodecyl mercaptan. These results are shown in Table 1.

Examples 1 to 7, Comparative Example 1 to 100 parts of vinyl chloride resin, 3 parts by weight of tribasic lead sulfate, and a predetermined amount of dioctyl phthalate (DOP) were added and mixed at high speed using a Henschel mixer to make the contents uniform. Stirring was performed, and when the mixture became uniform, a predetermined amount of the rubbery copolymer shown in Table 2 was blended and stirred. The obtained vinyl chloride resin composition was kneaded for 9' minutes at 180° C. using two 6-inch rolls. The obtained roll sheet was press-molded to prepare a sample for physical property evaluation, and various physical property evaluations were performed.

Comparison of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 2, comparison of Example 4 and Comparative Example 1'3, and comparison of Example 5 and 1 As is clear from the comparison with Examples 7 to 9, the comparison between Example 6 and Comparative Examples 10 to 11, and the comparison between Example 7 and Comparative Example 12, It can be seen that the vinyl chloride resin composition obtained by mixing the combinations is a material with an excellent balance between compression set characteristics and fluidity, and excellent mechanical strength.

1. 5,- □

Claims (3)

[Claims] (1) (a) For 100 parts by weight of vinyl chloride resin, (
b) A rubbery copolymer consisting of 55-80% by weight of conjugated diene, 20-45% by weight of α,β-unsaturated nitrile and 0-10% by weight of other copolymerizable monomers,
20 to 200 weight percent of a rubbery copolymer having an insoluble content in tetrahydrofuran of 50% by weight or more, a Q value of the tetrahydrofuran insoluble content below of 20 or less, and a Mooney viscosity (ML_1_+_4, 100°C) of 10 to 40. and (c) 0 to 200 parts by weight of a plasticizer. Q=W/W'W; Precisely weighed approximately 1 g of the rubbery copolymer insoluble in tetrahydrofuran and using it as a solvent, add 100 ml of tetrahydrofuran.
Weight (g) of the swollen rubbery copolymer containing the solvent after being immersed in the solution and left standing at 25°C for 24 hours W': Dry weight (g) of the swollen rubbery copolymer (2) (b) In the rubbery copolymer, the conjugated diene is butadiene, the α,β-unsaturated nitrile is acrylonitrile, and the insoluble content in tetrahydrofuran is 70 to 9
5% by weight, Q value 3.0 to 15.0, the vinyl chloride resin composition according to claim (1).