JPH04253751A - Abrasion resistance modifier for flexible vinyl chloride resin - Google Patents

Abstract

PURPOSE:To provide an additive which can improve the abrasion resistance of a flexible vinyl chloride resin. CONSTITUTION:An abrasion resistance modifier for a flexible vinyl chloride resin comprising a graft copolymer obtained by copolymerizing polymethyl methacrylate macromonomer with styrene and another vinyl monomer and comprising 3-50wt.% units of said macromonomer, 50-97wt.% units of said styrene monomer and 0-30wt.% units of said another radical-polymerizable monomer and polystyrene or a styrene polymer mainly consisting of styrene monomer units.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wear resistance modifier for soft vinyl chloride resins. The soft vinyl chloride resin composition to which the modifier of the present invention has been added has hardness and abrasion resistance, and is suitable for use in sheets, films, leather, hoses, wire covering materials, and daily goods. be done.

0002

2. Description of the Related Art Polyvinyl chloride resins, like nylon, polyester, polyethylene, etc., are used as general-purpose plastics for various purposes, and are broadly classified into hard vinyl chloride resins and soft vinyl chloride resins.

[0003] Soft vinyl chloride resin is a resin in which polyvinyl chloride is blended with a low molecular weight plasticizer such as DOP (dioctyl terephthalate) or a polymeric plasticizer such as aliphatic polyester. teeth,
There are various sheet materials, films, hoses, wire covering materials, etc.

Recently, in the above-mentioned applications of soft vinyl chloride resins, particularly in the field of electric wire coating materials, there has been an increasing demand for soft vinyl chloride resins that have even better wear resistance than before. A known method for improving the abrasion resistance of soft vinyl chloride resins is to blend resins with excellent abrasion resistance such as polyurethane, but in order to obtain sufficient abrasion resistance, highly abrasion resistant resins are needed. Since it is necessary to use a large amount of , there have been problems in that economic efficiency is lowered and other desirable physical properties are lost.

The present inventors have proposed a methyl methacrylate-styrene graft copolymer as a wear-resistance modifier that solves the above problems, and have previously applied for a patent. However, there remained the problem that the economical efficiency of soft vinyl chloride resin was somewhat impaired due to its use.

[0006]

[Problems to be Solved by the Invention] The present invention aims to provide a modifier that can improve the wear resistance of soft vinyl chloride resin without impairing its properties such as economic efficiency and mechanical properties. It is.

[0007]

[Means for Solving the Problems] As a result of intensive studies on methods for solving the above problems, the present inventors have found that a mixture of a graft copolymer and a styrene polymer having a specific chemical structure can be used as a soft vinyl chloride resin. The present inventors have discovered that wear resistance can be significantly improved while maintaining mechanical properties, and have completed the present invention.

That is, the present invention provides a polymer having a radically polymerizable group at one end of a polymer mainly composed of (a) methyl methacrylate monomer units, and having a number average molecular weight based on the total amount of all constituent units. 3-50% by weight of 2,000-20,000 macromonomer units, (b) 50-97% by weight of styrene monomer units, and (c) 0-30% by weight of other vinyl monomer units. A graft copolymer (A) which is
It is also an abrasion resistance modifier for soft vinyl chloride resin, which is made of a styrenic polymer (B) containing styrene monomer units as a main component.

The present invention will be explained in more detail below.

[Graft copolymer] The graft copolymer of the present invention is a polymer mainly composed of (a) methyl methacrylate monomer units (hereinafter referred to as MMA monomer units), which is radically polymerized at one end of the polymer. It is a graft copolymer obtained by radical polymerization of a macromonomer having a chemical group and a number average molecular weight of 2,000 to 20,000, (b) styrene, and optionally (c) other vinyl monomers.

[0011] As described above, the macromonomer in the present invention has a number average molecular weight of 2,000 to 20,000 and has a radically polymerizable group attached to one end of a polymer mainly composed of methyl methacrylate polymer units. It is a certain macromonomer.

[0012] The number average molecular weight of the macromonomer is 2,00
When it is less than 0, the molecular chain length of the branch component in the obtained graft copolymer is too short, and the anchoring effect to polyvinyl chloride is insufficient. On the other hand, when it exceeds 20,000, the copolymerizability with styrene is poor. In other words, unreacted macromonomers tend to remain, making it difficult to obtain a highly pure graft copolymer.

[0013]The number average molecular weight in the present invention is
Gel permeation chromatography (hereinafter referred to as GPC)
It is the number average molecular weight measured in terms of polystyrene.

The amount of MMA monomer units in the macromonomer used in the present invention is 80% based on the total amount of monomer units forming the polymer skeleton of the macromonomer.
It is preferable that it is at least % by weight. If the content of the MMA monomer unit is less than 80% by weight, the compatibility of the branch components of the resulting graft copolymer with polyvinyl chloride will be poor.

Examples of the radically polymerizable group of the macromonomer include (meth)acryloyl group, styryl group, allyl group,
Examples include a vinyl ether group, a (meth)acryloyl group and a styryl group are preferred, and a (meth)acryloyl group is particularly preferred.

The above-mentioned macromonomer can be synthesized by a living polymerization method such as an anionic living polymerization method, a grief transfer polymerization method or an immortal polymerization method, or a radical polymerization method as outlined below. Radical polymerization is preferred because it is less susceptible to impurities and can be easily produced industrially.

The method for producing a polymethyl methacrylate type macromonomer by a radical polymerization method is explained by using a mercaptan compound having both a functional group reactive with an epoxy group, such as a carboxyl group, and a mercapto group, as a chain transfer agent. , by radical polymerizing methyl methacrylate to obtain polymethyl methacrylate having a carboxyl group at one end of the molecule, and then subjecting it to an addition reaction with a compound having an epoxy group and a (meth)acryloyl group in the molecule, a macromonomer can be obtained. Obtainable.

In the present invention, other vinyl monomers that can be copolymerized with the macromonomer and styrene include aromatic ring-substituted styrenes, α-methylstyrene, vinylidene halides such as vinylidene chloride,
Vinyl esters such as vinyl acetate, vinyl ethers such as n-butyl vinyl ether, acrylic esters such as butyl acrylate, methacrylic esters such as 2-ethylhexyl methacrylate, acrylic acid, methacrylic acid, maleic anhydride, N -substituted maleimides, etc.

The structure of the graft copolymer obtained by copolymerizing the above polymerizable components is based on the total amount of all the structural units of the graft copolymer, and the above macromonomer units are 3 to 5.
0% by weight, 50 to 97% by weight of styrene monomer units and 0 to 30% by weight of other vinyl monomer units, more preferably 5 to 40% by weight of macromonomer units, 60 to 60% by weight of styrene monomer units. 95% by weight and 0-20% by weight of other vinyl monomer units.

If the amount of the macromonomer is less than 3% by weight, the amount of branch components introduced into the graft copolymer is too small;
It has poor compatibility with polyvinyl chloride, and on the other hand, if it exceeds 50% by weight, gelation tends to occur during the synthesis of the graft copolymer. If the amount of the macromonomer and the vinyl monomer other than styrene exceeds 30% by weight, the wear resistance of the soft vinyl chloride resin cannot be improved.

[0021] The graft copolymer can be produced by a radical polymerization method using a polymerization form such as solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization or dispersion polymerization. An outline of the case where suspension polymerization, which is a preferable polymerization form, is adopted is as follows.
Distilled water in which a suspending agent such as polyvinyl alcohol has been dissolved is stirred and heated, and a mixed solution of macromonomer, styrene, other vinyl monomers, and polymerization initiator is added thereto, and the reaction temperature is 50-50°C. The graft copolymer powder can be obtained by polymerizing at 90° C. for about 3 to 15 hours, and after the polymerization is completed, by filtering, washing with water, and drying.

[Styrenic polymer] Styrenic polymer is a polymer whose main component is styrene monomer unit. Specifically, styrene homopolymer, styrene and other vinyl monomers, etc. Copolymers, or graft copolymers made of an elastomer (described later) and a polymer formed from styrene or a monomer mixture mainly composed of styrene, and the like can be mentioned. In the present invention, the amount of monomer units other than styrene in the styrenic polymer is preferably 30% by weight or less based on the total amount of all monomer units.

Vinyl monomers that can be used with styrene include (meth)acrylic acid, (meth)acrylic acid ester, (meth)acrylonitrile, maleic anhydride, N-substituted maleides such as phenylmaleimide, and aliphatic compounds such as vinyl acetate. Examples include vinyl esters, aromatic vinyl esters, α-substituted styrenes such as α-methylsterene, and aromatic ring-substituted styrene derivatives such as p-alkylstyrene.

[0024] As the elastomer, polybutadiene,
Diene rubbers such as polyisoprene, polychloroprene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, styrene-isoprene block copolymer, etc. , ethylene-propylene copolymer, ethylene-propylene-diene monomer terpolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, and polyolefin rubbers such as chlorinated polyethylene, acrylic rubbers, and urethanes. Examples include rubber.

[Soft vinyl chloride resin] As a soft vinyl chloride resin that is effective using the modifier of the present invention, a soft vinyl chloride resin containing 20 to 200 parts by weight of a plasticizer per 100 parts by weight of polyvinyl chloride is used. is preferable, and more preferably a soft vinyl chloride resin containing 30 to 100 parts by weight of a plasticizer, and the soft vinyl chloride resin contains stabilizers normally used for soft vinyl chloride resins, such as lead stearate and stearic acid. Metal soaps such as barium, barium-zinc stabilizers, organotin stabilizers such as dibutyltin dilaurate, etc. may be added alone or in combination, and in addition, processing aids and ultraviolet absorbers may be added. , antioxidants, pigments, and inorganic fillers such as calcium carbonate may be added in appropriate amounts.

Examples of plasticizers include phthalic acid esters such as dioctyl phthalate or dibutyl phthalate, low molecular weight plasticizers such as trimellitic acid trialkyl esters, and adipic acid dialkyl esters, as well as various aliphatic polyesters and thermoplastics. Examples include polymeric plasticizers such as polyurethane.

The average degree of polymerization of polyvinyl chloride is 8
00 to 1,500 is preferable. If the average degree of polymerization of polyvinyl chloride is less than 800, the mechanical strength will be insufficient;
If it exceeds 00, moldability will be poor.

The above-mentioned polyvinyl chloride can be obtained by homopolymerizing vinyl chloride by suspension polymerization, solution polymerization, bulk polymerization, emulsion polymerization, etc., or by polymerizing the following copolymerized monomers.
It can be obtained by copolymerizing with vinyl chloride monomer in a proportion of 0% by weight or less. A preferred polymerization method is suspension polymerization, for example using a suspending agent such as partially saponified polyvinyl alcohol, a polymerization initiator such as an azo compound or an organic peroxide, and optionally a chain transfer agent such as a mercaptan compound. Polymerization temperature in aqueous medium: 30~
Polymerization may be carried out at 70°C.

The copolymerizable monomers include olefins such as ethylene and propylene, vinylidene halides such as vinylidene chloride, vinyl esters such as vinyl acetate, n
- Vinyl ethers such as butyl vinyl ether, acrylic esters such as butyl acrylate, methacrylic acid 2
- Methacrylic acid esters such as ethylhexyl and the like can be mentioned.

[Blend of Modifier] The wear resistance modifier of the present invention is composed of the graft copolymer and styrene polymer described above, and the weight ratio of the two is determined based on the total amount of the graft copolymer and the styrene polymer. The combined weight ratio is preferably 5 to 70% by weight, more preferably 10 to 50% by weight. If the weight proportion of the graft copolymer in the modifier is less than 5%, the mechanical strength of the soft vinyl chloride resin will be insufficient, and if it exceeds 70 weight%, it will impair the economic efficiency of the flexible vinyl chloride resin, which is not preferable.

The preferred blending ratio of the modifier of the present invention to the soft vinyl chloride resin is: per 100 parts by weight of the total amount of polyvinyl chloride and plasticizer in the soft vinyl chloride resin
The amount of the modifier is 3 to 30 parts by weight, more preferably 10 to 25 parts by weight.

[0032] The blending of the modifier into the soft vinyl chloride resin is as follows:
For example, it is made by melt-kneading at 120 to 200°C using a kneader such as a Banbury mixer, roll or extruder.

[0033]

[Example] The present invention will be explained in more detail by referring to Reference Examples, Examples and Comparative Examples below. Note that the parts described in each example are parts by weight.

Reference Example 1 400 parts of distilled water and a 5% aqueous solution of polyvinyl alcohol (Poval 420 manufactured by Kuraray Co., Ltd.) were placed in a glass flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer.
4 parts of calcium phosphate suspension (Supertite 10, manufactured by Nihon Kagaku Kogyo Co., Ltd.), and 0.2 parts of sodium dodecylbenzenesulfonate (Emar 2F, manufactured by Kao Corporation) were charged. A solution prepared by dissolving 25 parts of terminal methacrylate type polymethyl methacrylate macromonomer (Macromonomer AA-6 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 1.5 parts of azobisisobutyronitrile in 75 parts of styrene monomer was placed in a dropping funnel. I put it in. After heating, stirring, and raising the temperature of the flask to set the temperature of the internal liquid at 75° C., the monomer mixture was added dropwise from the dropping funnel over a period of 1 minute. The polymerization was completed by keeping at 75°C for 7 hours. After the reaction, the mixture was filtered, washed with water, dehydrated, and dried to obtain 90 parts of a solid styrene-methyl methacrylate graft polymer. The number average molecular weight of the obtained graft copolymer was 40.0 in terms of styrene by GPC.
It was 00.

Reference Example 2 The formulation shown below was mixed in a Henschel mixer to obtain a flexible polyvinyl chloride compound.

Vinyl chloride resin (TS- manufactured by Toagosei Kagaku Kogyo Co., Ltd.)
1100) 100 parts dioctyl phthalate

50 parts calcium carbonate

25 parts Epoxidized soybean oil
5th part
Ba-Zn liquid stabilizer

Part 1

Examples 1 to 4 and Comparative Examples 1 to 3 The graft polymer produced in Reference Example 1 and the commercially available polystyrene resin were added to the soft polyvinyl chloride compound produced in Reference Example 2 using a twin-screw screw in the ratio shown in the table. Melt blending was carried out at a resin temperature of 165° C. using an extruder (vent type co-rotating, diameter 29 mm, L/D=25) to obtain a pellet-shaped resin composition. The obtained resin composition was evaluated by a tensile test and a scrape test. The test method is as shown below.

Tensile Test The resin composition was pressed for 5 minutes at 180° C. using a small press to form a sheet of 100×100×1 mm. Punch out dumbbell-shaped test pieces from this sheet and use the JIS
The test was conducted at a tensile speed of 200 mm/min in accordance with K7113.

Scrape Test A sheet with a thickness of 1 mm was prepared in the same manner as above. This sheet was attached to the test equipment shown in Figure 1 so as to be perpendicular to the blade, and the blade was moved back and forth at a speed of 25 times per minute with a load of 1 kg, blade width of 2 mm, and stroke of 50 mm. evaluated.

[0040]

[Table 1]

[0041]

[Effect of the invention] As is clear from the results shown in Table 1, according to the examples in which the wear resistance modifier of the present invention was added,
The abrasion resistance of the soft vinyl chloride resin sheet has been improved, and the mechanical strength has hardly decreased. The modification effect is equivalent to or greater than that obtained when a graft copolymer containing no polystyrene is added alone. Since the amount of expensive graft copolymer used is small, it is considered to have a large economic effect and be of industrial significance.

[0042]

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a scrape test apparatus, in which a blade part 1 reciprocates in the horizontal direction while its tip scrapes the surface of a sample 3. 2 is an enlarged view of the tip of the blade portion 1 in FIG. 1.

[0043] The numbers in the figure indicate the following, respectively. 1 Blade 2 Load 3 Sample sheet 4 Support 5 Drive device 6 Support stand

Claims (1)

[Claims] [Claim 1] Based on the total amount of all constituent units, (
a) 3 macromonomer units with a number average molecular weight of 2,000 to 20,000, which have a radically polymerizable group at one end of a polymer mainly composed of methyl methacrylate monomer units
~50% by weight, (b) 50 to 97 styrene monomer units
% by weight, and (c) other vinyl monomer units from 0 to
30% by weight of the graft copolymer (A), and a styrenic polymer (B) containing styrene monomer units as the main component.
) is a wear-resistance modifier for soft vinyl chloride resin.