JPH01284541A - Heat-resistant vinyl chloride resin composition - Google Patents

Abstract

PURPOSE:To obtain a vinyl chloride resin composition improved in processability, heat resistance and impact resistance by mixing a vinyl chloride polymer with a specified rubber-modified resin comprising a rubber component, a vinyl aromatic monomer and an unsaturated carboxylic anhydride. CONSTITUTION:A rubber-modified resin is obtained by graftpolymerizing 100 pts.wt. monomer mixture comprising 60-95wt.% vinyl aromatic monomer and 40-5wt.% unsaturated dicarboxylic acid anhydride in the presence of 4-40 pts.wt. rubber component by a two-stage bulk polymerization process. In this graft polymerization, the proportion of the unsaturated dicarboxylic acid anhydride in the monomer mixture taking part in the polymerization is 2-11wt.% in the first stage before phase inversion and the one in the second stage after phase inversion is 12-45wt.%. 100 pts.wt. vinyl chloride polymer is mixed with 5-150 pts.wt. above rubber-modified resin.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides heat resistance and impact resistance useful for various molded products such as pipes, building materials such as pipes, home appliance parts, automobile parts, and miscellaneous goods. , relates to a vinyl chloride resin composition with excellent moldability.

[Conventional technology]

Vinyl chloride resin is widely used in various fields because it is inexpensive and has excellent physical and chemical properties, but it has the disadvantage of poor heat resistance and impact resistance, which limits the range of its use as a toilet. There is.

In the past, various attempts have been made to improve the heat resistance and impact resistance of vinyl chloride resins, and one of them is to add a specific monomer mixture to vinyl chloride resins in the presence of a rubber component. For example, a method is known in which a rubber-modified resin is blended by graft polymerizing a monomer mixture containing a vinyl aromatic monomer and an unsaturated dicarboxylic acid anhydride (JP-A-57-162745, 60-2487
No. 58, No. 61-14.3459, No. 62-5744
Publications such as No. 6).

[Problem to be solved by the invention]

However, with the above-mentioned known improvement methods, heat resistance and impact resistance are still insufficient, and it is difficult to improve heat resistance and impact resistance in order to expand the use of vinyl chloride resins. It could not be said that both characteristics could be fully satisfied.

In view of the above circumstances, an object of the present invention is to provide a vinyl chloride resin composition that has excellent heat resistance and impact resistance, in addition to the good processability inherent to vinyl chloride resins. It is said that

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors have found that by blending a specific rubber-modified resin with a vinyl chloride resin, the properties of heat resistance, impact resistance, and processability can be improved. Having learned that an excellent vinyl chloride resin composition can be obtained, the present invention was completed.

That is, the present invention comprises: A) 100 parts by weight of a vinyl chloride polymer, B) 60 to 9 parts by weight of a vinyl aromatic monomer in the presence of 4 to 40 parts by weight of a rubber component.
100 parts by weight of a monomer mixture consisting of 5% by weight and 40 to 5% by weight of an unsaturated dicarboxylic anhydride are added to the monomer mixture participating in the polymerization in the first step before phase inversion by a two-step bulk polymerization method. The proportion of unsaturated dicarboxylic acid anhydride in
in the range of 11% by weight, and in the second stage after phase inversion, the proportion of the same unsaturated dicarphonic anhydride as above is 12 to 45% by weight.
This relates to a heat-resistant vinyl chloride resin composition characterized in that 5 to 150 parts by weight of a rubber-modified resin obtained by graft polymerization is blended so that

[Structure and operation of the invention]

The vinyl chloride resin that is component A used in the present invention is a homopolymer of vinyl chloride, a copolymer of vinyl chloride and ethylene, propylene, vinyl acetate, etc., or a polymer of vinyl chloride and vinyl ethers, acrylic acid, methacrylate, etc. It contains a copolymer of acid conisteres, methacrylamide, acrylonitrile, etc., and may be produced by any production method such as bulk polymerization, suspension polymerization, emulsion polymerization, or solution polymerization. The degree of polymerization is not particularly limited, but is generally 60.
L preferably has a degree of polymerization of about 0 to 2,500.

The rubber-modified resin that is component B used in the present invention is a monomer mixture of a vinyl □ aromatic dimmer and an unsaturated dicarboxylic acid anhydride in the presence of a rubber component, which is prepared by a two-step bulk polymerization method. The ratio of unsaturated dicarboxylic acid anhydride in the above polymer mixture that participates in polymerization in the first step before phase inversion is 2.
-11% by weight, particularly preferably in the range 4-10% by weight, and in the second stage after the phase inversion, the proportion of unsaturated dicarboxylic acid anhydride is in the range 12-45% by weight, especially It is preferably obtained by graft polymerization so that the amount is in the range of 13 to 35% by weight. In other words, when the above monomer mixture is bulk polymerized in the presence of a rubber component, As the process progresses, the viscosity of the polymerization system gradually increases, and at a certain point, the viscosity suddenly decreases and the turbidity increases. This is known as a change in properties when the polymerization system undergoes phase inversion, but in the present invention, the copolymerization ratio of the monomer mixture involved in polymerization is changed as described above before and after such phase inversion. That is, in the two-stage bulk polymerization method, the proportion of unsaturated dicarboxylic anhydride in the monomer mixture is small in the first stage before phase inversion, and the proportion is increased in the second stage after phase inversion, The copolymerization ratio is changed.

According to the rubber-modified resin obtained by graft polymerization using such a specific two-step bulk polymerization method, when blended with vinyl chloride-based resin, unlike the conventionally known ordinary rubber-modified resin, It is possible to greatly improve both heat resistance and impact resistance, which are disadvantages of vinyl resins, without impeding the inherent processability. This improvement effect is due to the fact that in the first stage before phase inversion, the proportion of unsaturated dicarboxylic acid anhydride is in the range of 2 to 11% by weight, and in the second stage after phase inversion, the same proportion is in the range of 12 to 45% by weight. % range, the performance can be reliably achieved with good reproducibility, but if it deviates from the above range, either or both of heat resistance and impact resistance will be significantly reduced.

Rubber components used in the above graft polymerization include polybutadiene, styrene-butadiene block polymer, nitrile rubber, polyisobrengo J1, butadiene-acrylonitrile rubber, and EPDM (ethylene-propylene-diene block polymer). In addition, examples of vinyl aromatic monomers include styrene, α-methylstyrene,
-chlorostyrene, p-chlorostyrene, vinyltoluene, etc. Furthermore, examples of the unsaturated dicarboxylic anhydride include maleic anhydride, itaconic anhydride, chloromaleic anhydride, citraconic anhydride, and phenylmaleic anhydride. These rubber components, vinyl aromatic monomer and unsaturated dicarboxylic acid anhydride are each
You may use one type or mix and use two or more types.

The ratio of these raw material components to be used is, firstly, 4 to 40 parts by weight of the rubber component to 100 parts by weight of the monomer mixture consisting of the vinyl aromatic monomer and the unsaturated dicarboxylic acid anhydride. The amount is preferably 8 to 30 parts by weight.

If the rubber component is less than 4 parts by weight, the impact resistance will decrease, and if it exceeds 40 parts by weight, the heat resistance will decrease, so both are not preferred.

Next, the composition of the monomer mixture in the polymer is such that the vinyl aromatic monomer is 60 to 95% by weight, particularly preferably 65% by weight.
~93 weight percent and weight saturated dicarboxylic acid anhydride is 40-5
% by weight, particularly preferably from 35 to 7% by weight, and the proportion of unsaturated dicarboxylic acid anhydride in the first and second stages is such that the total amount is within the above range. It is adjusted so that Vinyl aromatic monomer is more than 95% by weight and unsaturated dicarboxylic acid anhydride is 5% by weight
If the content of the unsaturated dicarboxylic acid anhydride exceeds 40% by weight and the content of the vinyl aromatic monomer is less than 60% by weight, the molecular weight of the rubber-modified resin decreases, resulting in a decrease in impact resistance. Therefore, both are unfavorable.

In order to obtain the rubber-modified resin of the present invention by the specific two-step bulk polymerization method using such raw material components, for example, a predetermined amount of a solution in which the rubber component is dissolved in a vinyl aromatic monomer is charged into a polymerization kettle; Polymerize while stirring at a temperature of 90 to 120°C while adding a first vinyl aromatic monomer solution in which a predetermined amount of unsaturated dicarboxylic acid anhydride and an appropriate amount of polymerization initiator are dissolved,
Polymerization continues until phase inversion occurs. From the point at which phase inversion occurs, a second vinyl aromatic monomer solution containing a predetermined amount of unsaturated dicarboxylic anhydride and an appropriate amount of polymerization initiator is added to continue polymerization to reach the target conversion rate. What is necessary is to allow the polymerization to proceed until

The polymerization solution obtained in this way contains a solid component that does not participate in the polymerization, as well as a graft product in which a monomer mixture is graft-polymerized to a rubber component, as well as unreacted rubber components and polymers that do not participate in grafting. It contains a liquid component consisting of unreacted vinyl aromatic monomer (which acts as a polymerization solvent). Therefore, by drying this polymerization liquid under reduced pressure using a thin film distillation machine, a Flasher-1 extruder, etc. to remove the above-mentioned liquid components, the rubber modified resin of the present invention in the form of pellets or granules can be obtained. .

The molecular weight of the resin component excluding the rubber component in this rubber-modified resin (that is, the resin component other than the rubber component constituting the graft body and the resin component consisting of a polymer not involved in grafting) is not particularly regulated. , generally G
Weight average molecular weight by PC method is approximately 50.000 to 30
Preferably, it is in the range of 0,000.

The heat-resistant vinyl chloride resin composition of the present invention is prepared by blending the above-described rubber-modified resin as component B with the vinyl chloride polymer as component A and uniformly mixing. Here, the blending ratio of both of the above components is 5 to 150 parts by weight of component B to 100 parts by weight of component A, particularly preferably 8 parts by weight.
The amount is preferably 120 parts by weight. If component B is less than 5 parts by weight, heat resistance and impact resistance will decrease, and if it exceeds 150 parts by weight, processability will deteriorate, so both are not preferred.

The method for uniformly mixing components A and B is not particularly limited, and both components may be mixed in advance using a Henschel mixer, ribbon blender, etc., and then melt-mixed using a Hanbury, extruder, roll, etc. Alternatively, both components may be melt-kneaded while being quantitatively supplied to a continuous kneader.

The heat-resistant vinyl chloride resin composition of the present invention contains small amounts of polymeric processing aids, heat stabilizers, plasticizers, antioxidants, ultraviolet absorbers, fillers, lubricants, blowing agents, flame retardants, and pigments. etc. can be added as necessary.

(Effects of the Invention) The heat-resistant vinyl chloride resin composition of the present invention has good processability and exhibits well-balanced physical properties in heat resistance and impact resistance, so it can be used in building materials, automobile parts, and home appliances. It can be widely used for the various applications mentioned above.

〔Example〕

Next, the present invention will be specifically explained using reference examples, examples, and comparative examples. Hereinafter, parts and % mean parts by weight and % by weight, respectively.

Reference example 1 Polybutadiene rubber [trade name Diene 3 manufactured by Asahi Kasei Kogyo ■
5R) and 785 parts of styrene were charged into a polymerization pot and stirred to completely dissolve the rubber.

Thereafter, nitrogen was blown into the polymerization reactor to replace the gas, and the temperature was raised to 115°C. As soon as this temperature was reached, 22 parts of maleic anhydride (hereinafter referred to as MAN) and 0.0 parts of benzoyl peroxide (hereinafter referred to as BPO) were added. A first solution of 0.0071 parts dissolved in 321 parts of styrene was heated at 50°C for 2 hours.
It was added dropwise quantitatively over several minutes. At this time, the viscosity of the polymerization system decreased significantly, and it was recognized that a phase inversion occurred.

At this stage, a small amount of the polymerization system was sampled and the solid content was determined to be 25.9%. Further, the MAN content in this solid content was measured by °ζ analysis according to "Polymer Analysis Handbook", Nippon Analytical Kagaku Kintin, Asakura Shoten, P278 (1985), and was found to be 6.8%.

Subsequently, at the same temperature, 57.8 parts of MAN and BPoo,
A second solution prepared by dissolving 0071 parts in 321 parts of styrene was quantitatively added dropwise over 3 hours. After dropping, it was rapidly cooled to 50°C and sampled to measure solid bone.
It was 35.1%. The polymerization solution was dried under reduced pressure to obtain a rubber modified resin.

Reference Example 2 As shown in Table 1 below, the procedure of Reference Example 1 was repeated, except that the first solution and the second solution were combined and added in one stage over a period of 5 hours and 50 minutes. Polymerize as in the case,
A polymerization solution having a solid content of 36.2% was obtained, and this was dried under reduced pressure to obtain a rubber modified resin.

Reference Examples 3 to 6 The procedure was the same as in Reference Example 1, except that the amount charged in the polymerization pot, the polymerization temperature, the composition of each dropping liquid in the first stage and the second stage, and the two-dropping time were changed as shown in Table 1. The polymer was polymerized and then dried under reduced pressure to obtain a rubber-modified resin.

Reference example 7 Polybutadiene rubber (same as that used in reference example 1) 1
(10 parts, 314 parts of styrene, and 47 parts of α-methylstyrene)
1 part was placed in a polymerization pot and stirred to completely dissolve the rubber. After that, nitrogen was blown into the polymerization reactor to replace the gas, and the temperature was raised to 110°C, and as soon as this temperature was reached, the MA
A first solution in which 22 parts of N and 0.7 parts of BPOo were dissolved in 128 parts of styrene and 193 parts of α-methylstyrene was quantitatively added dropwise over 2 hours and 52 minutes. At this time,
The viscosity of the polymerization system decreased significantly, and it was observed that a phase inversion occurred.

At this stage, a small amount of the polymerization system was sampled and the solid content and MAN content were measured in the same manner as in Reference Example 1, and the solid content was 28.5% and the MAN content was 6.24%.

Subsequently, at the same temperature, 58 parts of MAN and 0 parts of BPoo
A second solution prepared by dissolving 7 parts of styrene in 128 parts of styrene and 193 parts of α-methylstyrene was quantitatively added dropwise over 3 hours. After the dropping was completed, the solid content was measured in the same manner as in Reference Example 1 and found to be 38.2%. The polymerization solution was dried under reduced pressure to obtain a rubber modified resin.

For each rubber-modified resin produced in Reference Examples 1 to 7 above, the rubber content, MAN content, and weight average molecular weight by CPC of the resin after rubber separation were determined from "Polymer Analysis Handbook" Japan Analytical Chemistry Kintin, Asakura Shoten, P27B (1
Analytical measurements were carried out according to 985). In addition, except for Reference Example 2 in which the two-step bulk polymerization method was not adopted, in each Reference Example, the polymer mixture [MAN and styrene (or this and α-methyl The MAN content (Xl) in the total amount of styrene) and the MAN content (X2) in the second stage after phase inversion were calculated according to the following formula. These results were as shown in Table 2 below.

M.

a: Solid content of the polymerization solution in the first stage b: Solid content of the final polymerization solution Z: Amount of rubber component charged into the polymerization pot Ml: Amount of MAN dropped in the first stage M2: MAN in the second stage Dripping amount Example 1 Vinyl chloride resin [trade name Sumirit 5X manufactured by Juju Chemical
-Jll'', polymerization degree +, O5O:+, the rubber modified resin obtained in Reference Example I, and various additives were mixed in a Henkel S'-- with the following composition.

Hinyl chloride resin 100 parts Rubber modified resin 30 parts Composite lubricant (manufactured by Henkel, 1 part, trade name G II-4) Octyl tin malate (Katsu BE 1.5 parts, trade name TM-188J, manufactured by Kako Co., Ltd.) Calcium stearate 1 Part 3: 2 parts of basic lead sulfate Next, this mixture was kneaded for 5 minutes with a hot roll heated to a surface temperature of 185°C to form a sheet, which was then kneaded at 190°C using a flat plate press.
Press molding was carried out for 10 minutes under the condition of 100 kg/crAl to prepare test pieces made of heat-resistant vinyl chloride resin compositions for each test described below.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1, except that the same amount of the rubber modified resin obtained in Reference Example 2 was used in place of the rubber modified resin i (I) in Reference Example 1.

Example 2 A test piece was prepared in the same manner as in Example 1, except that 40 parts of the rubber-modified resin obtained in Reference Example 3 was used instead of the rubber-modified resin obtained in Reference Example 1.

Comparative Example 2 A test piece was prepared in the same manner as in Example 2, except that the same amount of the rubber-modified resin obtained in Reference Example 4 was used in place of the rubber-modified resin obtained in Reference Example 3.

Comparative Example 3 A test piece was prepared in the same manner as in Example 2, except that the number of parts of the rubber-modified resin obtained in Reference Example 3 was changed to 3 parts.

Comparative Example 4 A test piece was prepared in the same manner as in Example 2, except that the blended amount of Go 1 obtained in Reference Example 3 and the modified resin was changed to 2.0 parts.

Example 3 A test piece was prepared in the same manner as in Example 1, except that 100 parts of the rubber-modified resin obtained in Reference Example 5 was used in place of the rubber-modified resin obtained in Reference Example 1.

Comparative Example 5 A test piece was prepared in the same manner as in Example 3, except that the same amount of the rubber-modified resin obtained in Reference Example 6 was used in place of the rubber-modified resin obtained in Reference Example 5.

Example 4 A test piece was prepared in the same manner as in Example 1, except that 30 parts of the rubber modified resin obtained in Reference Example 7 was used in place of the rubber modified resin obtained in Reference Example I.

Comparative Example 6 A test piece was prepared in the same manner as in Example 1, except that no rubber modified resin was mixed and kneaded.

Using each of the test pieces prepared in Examples 1 to 4 and Comparative Examples 1 to 6 above, heat distortion temperature, Izot impact strength, and melt flow rate 1. was measured in the following manner. Result is,
The results were as shown in Table 3 below. It should be noted that the higher the value of each of these measured values, the worse the heat resistance, impact resistance, and workability.

Hicut softening point: JIS K1206, B method Izot impact strength: JIS [6871, notched As is clear from the results in Table 3 above, the vinyl chloride resin composition according to the present invention has good processability. It can be seen that it has excellent heat resistance and impact resistance.

Claims (1)

[Claims] (1) In the presence of A) 100 parts by weight of a vinyl chloride polymer, B) 4 to 40 parts by weight of a rubber component, 6 parts by weight of a vinyl aromatic monomer.
100 parts by weight of a monomer mixture consisting of 0 to 95% by weight and 40 to 5% by weight of an unsaturated dicarboxylic acid anhydride was added by a two-step bulk polymerization method to remove the monomers involved in the polymerization in the first step before phase inversion. The proportion of unsaturated dicarboxylic acid anhydride in the mixture is in the range of 2 to 11% by weight, and the proportion of the same unsaturated dicarboxylic acid anhydride in the second stage after phase inversion is in the range of 12 to 45% by weight.
1. A heat-resistant vinyl chloride resin composition, characterized in that 5 to 150 parts by weight of a rubber-modified resin obtained by graft polymerization is blended within a range of 5 to 150 parts by weight.