JPS5998154A - Rigid resin composition - Google Patents

Abstract

PURPOSE:A composition capable of being molded stably under wide processing conditions, having high impact strength and improved weather resistance, obtained by blending a specific vinyl chloride-containing graft copolymer with methyl methacrylate polymer and vinyl chloride polymer. CONSTITUTION:(A) 5-60pts.wt. graft copolymer obtained by polymerizing vinyl chloride or a monomer mixture consisting essentially of vinyl chloride in the presence of an ethylene-vinyl ester copolymer or ethylene-acrylate copolymer and polyethylene (the amounts of them are >=15wt%, respectively, and the total amount of both components is <=85wt%) is blended with (B) 0.5-20pts.wt. methyl methacrylate polymer and (C) 100pts.wt. vinyl chloride polymer. Or a graft copolymer obtained by polymerizing vinyl chloride or the monomer mixture consisting essentially of vinyl chloride in the presence of EVA or EEA and polyethylene, and the component B is blended with the component C (the amount of each component is the same amount as the above-mentioned value).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hard resin composition that can be used under a wide range of processing conditions and that provides high impact strength and excellent weather resistance.

Vinyl chloride polymers (hereinafter referred to as PVC) are used in large quantities in building materials, vehicles, etc. because of their excellent physical properties, flame retardance, chemical resistance, and weather resistance, as well as their economic efficiency. Many of these products are used outdoors for long periods of time, and many products are required to have both high impact resistance and weather resistance.

Up to now, the following methods (1) to (4) have been known as methods for improving the impact strength and weather resistance of PVC.

That is, (1) ethylene-vinyl ester copolymer (E
VA), ethylene-acrylic ester copolymer (EE
A) Method of mixing one or more types of distoners such as chlorinated polyolefins (CPE) with PVC (2) EVA, EE
A, CPE, ethylene-propylene copolymer (EPR)
, ethylene-propylene-nonconjugated diene copolymer (EP
T), butyl rubber or its chlorinated product (IIR),
Epichlorohydrin rubber (CHR), (meth)acrylic acid ester-based copolymer (AR) or poly-IJ
, a method using a polymer obtained by polymerizing vinyl chloride in the presence of a polymer having a glass transition point of 120° C. or lower, such as j-refin (PE) (31EVA, EEA).

EPR, EPT, IIR, CHR%CPE, AR.

A polymer obtained by polymerizing vinyl chloride in the presence of PE etc.
Method of mixing into VC, (41EVA, EEA.

One or more polymerizable monomers selected from (meth)acrylic acid esters, aromatic vinyl compounds, and vinyl cyanide compounds are polymerized in the presence of EPT, EPR, IIR, CPE, AR, PE, etc. A method is known in which the polymer obtained by the above method is mixed with PVC.

However, these conventional methods have many problems in actual processing and use, and are not necessarily at a level that is satisfactory to users. In other words, (1) In this method, in order to improve impact resistance, an elastomer that is semi-compatible with PVC is used, so under normal cross-wire conditions, dispersion is insufficient and no reinforcing effect is often achieved. On the other hand, it is possible to use a type of nidistomer that is highly compatible with PvC, but in this case, not only will the impact resistance strength be reduced, but the hardness of the product will also be reduced. Furthermore, according to this method, the softening temperature of the mixture is significantly lowered, so that it is necessary to limit the use temperature of the product to a low level.

Furthermore, in examples using EVA, the effect of improving impact strength is small, and in examples using CPE, weather resistance stability is poor.

Although weather resistance stability and impact strength can be improved by using both in combination, a decrease in the softening temperature is unavoidable.

What was obtained by the method (2) (EV as a nidistomer)
A, products using EEA or EPR are commercially available), because a part of the nidistomer is chemically bonded to PVC, and the polymer is a uniform dispersion of PVC and elastomer, so it is easy to use. This polymer has the advantage of being able to obtain a product with a high impact value, and the ratio of nidistomers in the polymer can also be reduced5, resulting in a small decrease in softening temperature and excellent weather resistance. The problem is that the narrow processing width causes a sudden drop in impact strength even if the length becomes slightly longer or the heating temperature rises slightly. In addition, in order to obtain this polymer as a powder that is easy to mix with various compounding agents similar to ordinary PVC, it is necessary to dissolve the nidistomer in vinyl chloride or to finely powder it during one polymerization, making the single polymerization operation complicated. Become.

According to the method (3), it is possible to achieve excellent dispersibility of PvC and elastomer more economically than with the method (2), and there are commercial examples of products using EVA as the nystomer. many. However, the biggest problem with this method remains that the narrow processing width remains.There are examples in which powdered polymers obtained by polymerizing in one or multiple stages have been commercialized as acrylate impact additives. many. According to this method, the mixture can be processed over a wide range, so products with high impact strength can be stably manufactured.
Although the softening temperature decreases little, the weather resistance stability of impact strength is not necessarily sufficient. Another problem with this method is that the impact strength varies greatly depending on the type of notch shape.

The inventors of the present invention have diligently studied the conventional methods for obtaining weather-resistant and impact-resistant resin products as described above, and have improved the narrow processing width of method (3), which inherently has excellent weather resistance. As a result of research on methods for molding, it was found that using a specific graft copolymer can be stably molded under a wide range of processing conditions, and has better weather resistance than PvC, which has a higher softening temperature. The present inventors have discovered that it is possible to obtain a composition that can provide a type of resin product, and have completed the present invention.

That is, the present invention provides (1) ethylene-vinyl ester copolymer (EVA) or ethylene-acrylic acid ester copolymer (EEA) (A) and polyethylene (B
It is obtained by polymerizing vinyl chloride or a monomer mixture (C) mainly composed of vinyl chloride in the presence of (
A) and fB) are each greater than 15% by weight, and (
The total amount of A) and (B) is 85% by weight or less.

5 to 60 parts by weight of graft copolymer (I), 0.5 to 20 parts by weight of methyl methacrylate polymer (II), and pv
(2) EVA or EEA prisoner,
It is obtained by polymerizing vinyl chloride or a monomer mixture mainly composed of vinyl chloride (C) in the presence of polyethylene (B) and a methyl methacrylate polymer (I), excluding (II). A graft copolymer (■゛) and pvco, and (I
ll 1o o per part by weight, the polymer portion excluding (II) in (■') is 5 to 60 parts by weight, and (110 is 0.5 to 0.5 parts by weight)
The present invention provides a hard resin composition characterized in that the amount of the hard resin composition is 20 parts by weight.

EVA or EEA (A) used in the production of graft copolymer (I) or (■') in the present invention has an ethylene content of 20 to 80% by weight. If the ethylene content is less than 20% by weight, the glass transition point is too high,
Impact resistance strength is insufficient.

If it exceeds 80% by weight, compatibility with vinyl chloride becomes poor. Examples of vinyl esters in EVA include vinyl acetate, vinyl propionate, vinyl laurate, and examples of acrylates in EEA include methyl acrylate, ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, hydroxypropyl. Examples include acrylate, 2-ethylhexyl acrylate, and the like. Along with these vinyl esters and acrylic esters, carbon monoxide, vinyl ether,
Copolymerization of olefins other than ethylene may also be used.

Polyethylene (B) may include ethylene homopolymers produced by high-pressure, medium-pressure, or low-pressure methods, copolymers of ethylene with 10% by weight or less of other monomers, or 15% of these polyethylenes. Examples include chlorinated compounds and metal ion compounds containing less than % by weight, and those having a melt index value of about 0.01 to 50 at 190°C can be used.

With the vinyl chloride polymerized in the presence of (A) and (B), conventional copolymerizable monomers can be used, if desired, in amounts up to 30% by weight in the mixture with the vinyl chloride. Examples include monoolefins, vinyl ethers, (meth)acrylates, vinyl esters, unsaturated acids, and the like.

The graft copolymer (I) of the present invention and EVA (indicated in the polymer portion excluding II) are E E A (A) and polyethylene (B).
The content of (A) and (B) is at least 15% or more, and the total amount of (A) and (B) is 85% by weight or less. If the amount of (A) is less than 15% by weight, the reinforcing effect as an impact auxiliary agent will be small, and (B)
If the amount is 15% by weight or more, the range of processing conditions that give a high impact value will be narrowed. Furthermore, if the total amount of (A) and (B) exceeds 85% by weight, the proportion of (A) and (B) that are not chemically bonded to vinyl chloride will increase, and the reinforcing effect will not only decrease. , the softening point of the composition is significantly lowered, which does not meet the object of the present invention.

Incidentally, the graft copolymers (1) and (I') are produced by a conventional method. The shapes of (A) and CB) to be subjected to the polymerization system are not particularly limited, and may be pellets or sheets.

It may be in the form of a veil, powder, aqueous dispersion, or the like.

However, (A) is often difficult to dissolve in vinyl chloride unless it has a specific composition, or the viscosity of the solution is high, making operation difficult.
) in a powder form that is easily mixed with PVC (UL), it is preferable to provide (A) and (B) to the polymerization system as a powder or an aqueous dispersion.

The graft copolymer (I) or the polymer portion excluding (IQ) is used in an amount of 5 to 60 parts by weight, preferably 10 to 50 parts by weight, based on 0 parts by weight of PVCQIII O0. If it is less than 5 parts by weight, the effect of improving impact strength is small and is not practical, and if it exceeds 60 parts by weight, the softening point of the composition will be significantly lowered.

A methyl methacrylate polymer (a polymer containing 400 parts by weight or more of methyl methacrylate component is used.A specific example thereof is methyl methacrylate as a main component, and a (meth)acrylic acid ester and an aromatic vinyl compound. , a vinyl cyanide compound, etc. (in some cases, a small amount of a polyfunctional acrylic acid monomer having two or more unsaturated bonds, an allyl compound, etc. may be coexisting) is emulsion copolymerized in one or multiple steps. The gel content is 50
Examples include polymers with a weight of less than t%. Among these, preferred are polymers in which 50% by weight or more of the non-gel portion has a molecular weight of 10QOOO or more.

Other specific examples include block copolymers in which at least one component is methyl methacrylate.

The methyl methacrylate polymer (IT), including the case where it is contained in the graft copolymer (1'),
It is blended in an amount of 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight, per 1100 parts by weight of It. If the amount is less than 0.5 parts by weight, the composition tends to lack strength at the initial stage of cross-wiring, and secondary processability such as vacuum formability deteriorates. On the other hand, if it exceeds 20 parts by weight, processability becomes extremely poor.

The PVC used in the present invention is not particularly limited as long as it is used for ordinary building materials and hard products, but it is usually a homopolymer of vinyl chloride or 80% by weight or more of vinyl chloride. A copolymer with 20% by weight or less of a copolymerizable monomer or a chlorinated product thereof, which has an average degree of polymerization of about 400 to 1500 as measured by the method of JIS K6721, is used. If it is less than 400, the workability is excellent, but the impact resistance is low, and if it is more than 1500, the workability is poor.

It goes without saying that the composition of the present invention can further contain conventional plasticizers, stabilizers, ultraviolet absorbers, antioxidants, lubricants, pigments, fillers, reinforcing agents, etc., as necessary. do not have. Molding of this composition can be carried out in a conventional manner, and the processing conditions can be selected from a wide range. In addition, the obtained molded product exhibits excellent weather resistance, impact resistance, and heat resistance, and is therefore highly useful as general hard products such as building materials, vehicles, agricultural and fishery materials, etc.

Next, the present invention will be explained using examples. Note that the number of parts is based on weight.

Example 1 The raw materials for polymerization (unit: g) shown in Table 1 were charged into a stainless steel autoclave and polymerized at 50° C. for 12 hours, and then the polymer was collected, dried, and the amount recovered was measured. Next, the resulting polymer is appropriately pulverized or directly processed at 18
The graft copolymer under the sieve was obtained by passing it through a mesh sieve.

Next, mix the ingredients shown in Table 2 in the indicated weight proportions using a mill roll at 170°C for 3 minutes (mixing condition a), then at 180°C.
Mix for 10 minutes at 170°C (mixing condition B) or 6 minutes at 170°C (mixing condition C) to form a 1 mm thick sheet, stack 3 layers and press at 180°C for 5 minutes to form a 3 mm thick sheet.
A thick sample sheet was prepared.

The impact strength of this sample (JIS K-7111) and hardness (
JIS K-7202), softening temperature (JIS K-67
45), weather resistance (for items with high impact strength, impact strength J
ISK-7111), color tone change (visual observation), and presence or absence of chalking (visual observation)]. The results are shown in Table 2.

Example 2 50 parts of polyvinyl chloride with an average degree of polymerization of 1050, chlorine content of 67 parts, 5 parts of chlorinated polyvinyl chloride with an average degree of polymerization of 700
0 parts, 35 parts of graft copolymer A used in Example 1,
4 parts of methyl methacrylate-styrene block copolymer having a weight average molecular weight of 60QOOO and 50% methyl methacrylate were mixed in the same manner as in Example 1, and pressed to obtain a sample.The results are as follows. It is.

Mixed condition b: Is gf1 impact force kl normal?・cIn/cJ) 105
102 Hardness 110 11
5 Softening temperature ("C) 75 80 Impact strength after 000 hours ky-α/c1 84 89 Color tone change None None Chalking None None Patent applicant Zeon Corporation

Claims (2)

[Claims] (1) Polymerizing vinyl chloride or a monomer mixture mainly composed of vinyl chloride (C) in the presence of an ethylene-vinyl ester copolymer or an ethylene-acrylic ester copolymer (A) and polyethylene (B). Graft copolymers (■) obtained by 60 parts by weight of a methyl methacrylate polymer (II) o, s~20 parts by weight and 100 parts by weight of a vinyl chloride polymer α11). (2) Ethylene-vinyl ester copolymer or ethylene-acrylic ester copolymer (A), polyethylene (
A polymer portion obtained by polymerizing vinyl chloride or a monomer mixture mainly composed of vinyl chloride (C) in the presence of B) and a methyl methacrylate polymer (II), excluding (■) A graft copolymer (vinyl chloride polymer QII) in which each of (A) and (B) is more than 15% by weight and the total amount of (A) and (B) is 85% by weight or less. A hard resin composition consisting of 5 to 60 parts by weight of the polymer portion (excluding (n) in ■) and 0.5 to 20 parts by weight of (II) per 100 parts by weight of Q11. thing.