JPH06136216A - Vinyl chloride-based resin molding excellent in heat resistance - Google Patents

Abstract

PURPOSE:To obtain a vinyl chloride-based resin molding excellent in heat resistance by using a copolymer containing a 6-membered ring acid anhydride unit and a vinyl chloride-based polymer as essential components and dispersing a prescribed amount of the copolymer into a prescribed size or above in the molding. CONSTITUTION:This molding comprises (A) a copolymer, containing >=3wt.% 6-membered ring acid anhydride unit of the formula (R1 and R3 are H or methyl) and having 0.01-5dl/g reduced viscosity (measured by using a solution prepared by dissolving 0.15g copolymer in acetone to provide 0.5dl at 25 deg.C), preferably a copolymer, composed of 13-95wt.% methyl methacrylate, 1-70wt.% aromatic vinyl compound, 3-85wt.% 6-membered ring acid anhydride and 0.1-20wt.% methacrylic acid and (B) a vinyl chloride-based polymer, containing 60-100wt.% vinyl chloride and having 0.01-20dl/g reduced viscosity (measured by using a solution obtained by dissolving 0.15g copolymer in nitrobenzene to provide 0.5dl at 30 deg.C) at (0.1-500/(99.9-50) weight ratio of the components (A)/(B). The molding has an island-in-sea structure in which the component (A) is dispersed into a particulate form and the content of the particles having 1-15mum maximum length of the dispersed component (A) is >=10wt.%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vinyl chloride resin molded article having excellent heat resistance.

[0002]

2. Description of the Related Art Vinyl chloride resin has excellent properties such as water resistance, acid resistance, alkali resistance, flame retardancy and electrical insulation.
It is used in a wide range of applications such as pipes, joints, plates, films and sheets, and bottles. Vinyl chloride resins generally have low heat resistance, and their applications have been limited. However, in recent years, among the applications of vinyl chloride resins, those having excellent properties of the resins, such as flame retardancy and electrical insulation, and excellent heat resistance are being demanded.

As methods for improving the heat resistance of vinyl chloride resins, various studies have been made so far, such as intermolecular crosslinking, copolymerization, improvement of molecular structure (low temperature polymerization), and post-chlorination. The moldability is deteriorated at the same time that the heat resistance is improved, or the heat resistance improving effect is inferior. Further, there is a method of improving heat resistance by adding an acrylic resin, an ABS resin, a styrene resin, etc. to a vinyl chloride resin, but the heat resistance improving effect tends to be low.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to impart high heat resistance without impairing the characteristics of vinyl chloride resin.

[0005]

Means for Solving the Problems The inventors of the present invention have earnestly studied for the development of a vinyl chloride resin molded product having improved heat resistance, and as a result, have found that a copolymer containing a 6-membered cyclic anhydride unit is used. It has been found that the object is achieved by blending, and the present invention has been completed. That is, the present invention

[0006]

[Chemical 2] [Wherein R ₁ and R ₂ in the formula (1) are hydrogen atoms or methyl groups] and a copolymer (I) containing a 6-membered cyclic anhydride unit, and a vinyl chloride polymer (II And (2) are essential components, and the molded product has a sea-island structure in which the copolymer (I) is dispersed in the form of particles, and thus relates to a vinyl chloride resin molded product with greatly improved heat resistance.

The copolymer (I) containing a 6-membered cyclic acid anhydride unit used in the present invention contains at least one or more ethylenically unsaturated monomer units in addition to the 6-membered cyclic acid anhydride. It is a copolymer. As the ethylenically unsaturated monomer unit, methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl methacrylate,
Acrylic acid and methacrylic acid esters such as t-butyl-substituted cyclohexyl methacrylate, aromatic vinyls such as styrene and α-methylstyrene, and methacrylic acid, acrylic acid, vinyl chloride, vinyl acetate, acrylonitrile, ethylene, propylene, etc. Generally, a radically polymerizable monomer can be used. Among these ethylenically unsaturated monomer units, methyl methacrylate, styrene, α-methylstyrene and methacrylic acid are particularly preferable. The 6-membered cyclic acid anhydride unit has an effect of improving heat resistance.

Further, the methyl methacrylate unit improves the properties such as mechanical strength and oil resistance of the polymer containing 6-membered cyclic anhydride. Further, the styrene unit improves its properties such as mechanical strength and water resistance. The α-methylstyrene unit not only improves its water resistance but also heat resistance. When the copolymer (I) containing these component units is mixed with a vinyl chloride resin and molded, a molded product having extremely good heat resistance is obtained.

The amount of the 6-membered cyclic acid anhydride in these copolymers must be 3% by weight or more. If less than 3% by weight,
The effect of improving the heat resistance of the copolymer (I) itself is not sufficient, so that the vinyl chloride resin molded article of the present invention in which the copolymer is blended and molded has a low effect of improving the heat resistance and is not preferred.

Among the above copolymers (I), particularly,
(A) 6-membered cyclic anhydride unit 3 to 85% by weight (B) methyl methacrylate unit 13 to 95% by weight, (C) aromatic vinyl unit 1 to 70% by weight, and (D) methacrylic acid unit 0 It is preferable to use a copolymer having a composition of 0.1 to 20% by weight.

In this copolymer, the upper limit of the amount of 6-membered cyclic anhydride unit is 85% by weight, preferably 75% by weight, more preferably 50% by weight. If it exceeds 85% by weight, the water resistance is extremely reduced, and as a result, the properties of the vinyl chloride resin molded product are also deteriorated. The amount of methyl methacrylate units is 13 to 95% by weight, preferably 15 to 88% by weight. If it is less than 13% by weight, the mechanical strength is not sufficient. On the other hand, if it exceeds 95% by weight, the amount of the 6-membered cyclic anhydride introduced is not sufficient, and the heat resistance and the improving effect are low. Therefore, the heat resistance of the vinyl chloride resin molded product is not sufficiently imparted.

The amount of aromatic vinyl units is 1 to 70% by weight,
It is preferably 5 to 50% by weight. The aromatic vinyl unit compensates for the low water resistance of the 6-membered cyclic anhydride, and at the same time contributes to the improvement of the mechanical strength, but when it is less than 1% by weight, these effects are not sufficient, and 70% by weight. If you exceed
The amount of 6-membered cyclic anhydride introduced is not sufficient, and the heat resistance and the improvement effect are low. Therefore, the heat resistance of the vinyl chloride resin molded product is not sufficiently imparted.

Methacrylic acid is a necessary component for forming a 6-membered cyclic anhydride unit. The copolymer containing the component is heat-treated to form a 6-membered cyclic anhydride unit by dehydration or dealcoholization, but methacrylic acid remains in the copolymer without being completely consumed. .
The amount of methacrylic acid units in the copolymer (I) of the present invention is
It is 0.1 to 20% by weight, preferably 1 to 10% by weight. If it exceeds 20% by weight, dehydration or dealcoholization occurs during molding, which causes foaming or the like, which is not preferable.

Further, the above-mentioned copolymer used in the present invention is
A solution obtained by dissolving 0.15 g thereof in acetone to make 0.5 dl has a reduced viscosity at 25 ° C. of 0.01 to 5.0 dl /
g, preferably 0.05 to 1.0 dl / g. Generally, vinyl chloride polymers have poor thermal stability, so that the reduced viscosity of the copolymer (I) is 1.0 dl / g.
If it exceeds the range, decomposition due to heat generation due to shearing tends to occur in the blending of the vinyl chloride polymer, which is not preferable. On the other hand, when the above reduced viscosity is less than 0.01 dl / g, the strength of the obtained vinyl chloride resin molded product is low, which is not preferable.

The above-mentioned copolymer (I) is usually produced by copolymerizing an ethylenically unsaturated monomer with methacrylic acid and then heat-treating this copolymer to form a 6-membered cyclic acid anhydride. To be done. As the copolymerization method, all of the usual radical polymerization methods are used, and suspension polymerization, bulk polymerization and solution polymerization are particularly preferable. As a means for forming the 6-membered cyclic acid anhydride unit, an extruder equipped with a devolatilizing device, a residence devolatilizing device, or the like can be used.

As the vinyl chloride polymer (II) used in the present invention, polyvinyl chloride and a monomer which can be copolymerized with a vinyl chloride monomer, if necessary, such as vinyl acetate, ethylene, propylene, It includes a vinyl compound copolymer obtained by copolymerizing with a monomer such as vinylidene chloride or acrylonitrile and containing 60% by weight or more of a vinyl chloride polymer unit, and further includes a post-chlorinated product. These vinyl chloride polymers (II) are prepared by dissolving 0.15 g of the vinyl chloride polymer in nitrobenzene to give a solution having a reduced viscosity at 25 ° C. of 0.01 to 20 dl / g, preferably 0.05 to 1
It should be 0 dl / g, and more preferably 0.1 to 5 dl / g. When the reduced viscosity is less than 0.01, the mechanical strength of the resulting composition is insufficient, and when the reduced viscosity exceeds 20, the moldability is insufficient, which is not preferable.

The vinyl chloride polymer can be produced by a usual radical polymerization. A method such as suspension polymerization is particularly preferable. The blending amount of the copolymer (I) containing a 6-membered cyclic acid anhydride and the vinyl chloride-based polymer (II) is such that the vinyl chloride-based polymer (I) is contained in an amount of 0.1 to 50 parts by weight. Combined (II) 99.9-50
Parts by weight are preferred. More preferably, the copolymer (I) 1
~ 50 parts by weight of vinyl chloride polymer (II) 99 ~
It is 50 parts by weight. When the blending amount of the copolymer (I) containing a 6-membered cyclic acid anhydride is less than 0.1 part by weight, the heat resistance improving effect of the obtained molded article is small, which is not preferable. Also, 50
If the amount is more than the amount by weight, the flame retardancy of the vinyl chloride resin is impaired, which is not preferable.

The molded article of the present invention has the following characteristics: (a) When the ultrathin section of the molded article is observed with a transmission electron microscope, the copolymer (I) is dispersed in a particulate form in the molded article. The copolymer (I) having a sea-island structure in a state of (b) contains particles having a maximum length of 0.1 to 15 microns, and (c) all particles occupy. Total area 10
When it is 0%, the total area of particles shown in (b) is 10%.
The molded product has improved heat resistance of the vinyl chloride resin characterized by the above.

The vinyl chloride resin molded article of the present invention is obtained by dry-blending the copolymer (I) and the vinyl chloride polymer (II), and then rolling, a Banbury mixer, various mills, a screw type kneader, and the like. It can be produced by mechanically kneading while heating with a mixer or a blender. The size of the particles of the copolymer (I) in the resulting molded article is determined by the copolymer (I) and vinyl chloride polymer (I
It varies depending on the composition, molecular weight and shape of I), and also varies depending on the kneading method, kneading conditions (shear, temperature) and the like. Further, the shape of the particles changes not only into a spherical shape, but also into a rod shape or a string shape.

In the present invention, when an ultrathin section of a molded product is observed with a transmission electron microscope, the maximum length is 0.1.
It should be ~ 15 microns, preferably 0.2-15 microns. Further, when the total area occupied by all the particles of the dispersed copolymer (I) is 100%, the total area of the particles having the maximum length is 10% or more, preferably 20% or more, more preferably 30% or more. It is necessary (the area ratio can be determined by cutting out all the particles in a transmission electron micrograph and measuring the weight ratio).

If less than 10% of particles have a maximum length of 0.1 to 15 microns, the resulting molded article has a low heat resistance improving effect. The maximum particle length in the present invention is shown in FIG.
As shown in, the two points (A, B) that are most distant from each other on the outer circumference of the particle are connected by a straight line, and the length (X) is defined.
Further, parallel lines L ₁ and L ₂ circumscribing the particle are set in parallel with a straight line connecting A and B, and a rectangle or a square is created by a parallel line that passes through A and B at a right angle to this line and When the length is Y, it is preferable that a large number of particles having a ratio of X and Y (X / Y) of 1.2, preferably 1.5 or more are contained. When the ratio of X and Y (X / Y) is large, the heat resistance tends to be improved.

The vinyl chloride resin molded article of the present invention may contain an antioxidant, a heat stabilizer, a lubricant, an ultraviolet absorber, a colorant, a pigment, a filler, a flame retardant and the like depending on the purpose. A graft copolymer such as ABS or MBS may be added for the purpose of improving impact resistance. In addition, other resins such as acrylic resin and vinyl acetate resin can be added.

The vinyl chloride resin molded product of the present invention is used for generally used vinyl chloride resin products, for example, pipes / joints for water supply, agriculture, equipment / wastewater, plates such as flat plates and corrugated plates. Of course, it can be used for food packaging, non-food packaging, industrial films and sheets, building materials, electric circuit materials, profile extrusions such as lighting equipment, food bottles, non-food bottles, etc. It can also be used for new applications that could not be used because of its poor heat resistance.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Each property was measured by the following methods. (1) Reduced viscosity [Copolymer (I) and vinyl chloride polymer (II)] 0.15 g of the material is dissolved in acetone or nitrobenzene in a 0.5 dl volumetric flask. Using a Canon Fenske viscometer 50 # at 25 ° C. or 30 ° C., the flow-down seconds (t ₁ ) and the acetone or nitrobenzene flow-down seconds (t ₀ ) were measured. It was calculated by the following formula.

[0025]

[Equation 1] (2) Vicat Softening Temperature; ASTM D-1525 (3) Tensile Strength; ASTM D-638 (4) Particle Dispersion Morphology Observation: Three or more types of ultrathin sections were cut from a molded product by a microtome and various sections were cut. It was magnified 25,000 times with a transmission electron microscope, and the size and amount of particles were observed with a photograph of size 10 × 15 microns.

Examples 1 to 4 [Preparation of copolymer (I) containing 6-membered cyclic anhydride] 36.0 parts by weight of methyl methacrylate, 4.5 parts by weight of styrene,
Methacrylic acid 4.5 parts by weight, α-methylstyrene 15 parts by weight, t-butanol 40.0 parts by weight, 1,1-di-t
A mixed solution of 0.05 parts by weight of ert-butylperoxy-3,3,5-trimethylcyclohexanone and 0.3 parts by weight of n-octyl mercaptan was prepared, and this mixed solution was continuously added at a rate of 0.5 l / hr. The mixture was fed to a jacketed complete mixing reactor having an internal volume of 2 liters and polymerized at a temperature of 125 ° C. Further, it was continuously supplied to a high-temperature devolatilization apparatus in which the degree of polymerization was set to 260 ° C. to remove unreacted substances and produce a 6-membered cyclic acid anhydride. As a result of neutralization titration of this copolymer, composition analysis by an infrared spectrophotometer and the magnetic resonance measuring device, 64% by weight of methyl methacrylate unit, 12% by weight of styrene unit, 11% by weight of 6-membered cyclic anhydride unit. ,
Methacrylic acid 3% by weight, α-methylstyrene 10% by weight
Met. The reduced viscosity of the obtained copolymer is 0.11 dl.
/ G, the Vicat softening temperature was 138 ° C. (Vinyl chloride resin molded product)

A powdery vinyl chloride polymer (II) (TK-1000 manufactured by Shin-Etsu Chemical Co., Ltd.) in the proportions shown in Table 1, the above-mentioned pelletized copolymer, and a lead heat stabilizer (3 to 100 parts of resin).
Part) after dry blending, and using a hot roll 17
After melt-kneading at 0 ° C., a sheet-shaped molded product was obtained by a press molding machine set at 170 ° C. The characteristics of the obtained molded product are shown in Table 1. The vinyl chloride resin used had a reduced viscosity of 0.9.

[0028]

[Table 1] (Note) The ratio of the total particle area of the copolymer (I) having the maximum length defined in the text of 0.1 to 15 microns to the total area of all particles The copolymer (I) of Examples 1 to 4 The particles included those with a maximum length of 0.01 micron to 1.2 microns.

Example 2 (Preparation of Copolymer (I) Containing 6-Membered Cyclic Acid Anhydride) In the same manner as in Example 1, the prepared solution was prepared with methyl methacrylate 2
2.5 parts by weight, α-methylstyrene 26.3 parts by weight, methacrylic acid 26.3 parts by weight, t-butanol 25.0 parts by weight, 1,1-di-tert-butylperoxy-3,
0.05 parts by weight of 3,5-trimethylcyclohexanone,
It was polymerized with 0.02 part by weight of n-octyl mercaptan.
The composition of the obtained copolymer (I) was as follows: methyl methacrylate unit 40% by weight, α-methylstyrene unit 18% by weight,
6-membered cyclic anhydride unit 29% by weight, methacrylic acid unit 13
% By weight, reduced viscosity was 0.35 dl / g, and Vicat softening temperature was 172 ° C. Vinyl chloride polymer (II) 90
A molded product was obtained in the same manner as in Example 1 except that 10 parts by weight of this copolymer (I) was added to the heating roll temperature of 190 ° C. The obtained vinyl chloride resin molded product had a Vicat softening temperature of 99 ° C. and a tensile strength of 530 kg / cm ² .

Further, the obtained molded product had a sea-island structure, and the dispersion form of the particles was 35%. Figure 1 shows a transmission electron micrograph (2) of an ultrathin section cut from a molded product.
5000 times). The particles of the copolymer (I) contained particles having a maximum length of 0.01 micron to 0.4 micron.

[0031]

As described above, according to the present invention, it is possible to improve the heat resistance, which has been a drawback of the vinyl chloride-based polymer, without impairing the characteristics of the vinyl chloride-based polymer, and to further improve its utility. Can be expanded.

[Brief description of drawings]

FIG. 1 is a part of a transmission electron micrograph of an ultrathin section cut out from the molded product obtained in Example 2.

FIG. 2 is a diagram illustrating a method for measuring the size of particles shown in FIG.

Claims (3)

[Claims] Claims: At least 3% by weight of a 6-membered cyclic acid anhydride unit represented by the formula [ ₁ and R ₂ in the formula (1) is a hydrogen atom or a methyl group], and 0.15 g of this is dissolved in acetone The solution containing 0.5 dl contains a copolymer (I) having a reduced viscosity of 0.01 to 5.0 dl / g at 25 ° C. and 60 to 100 wt% of a vinyl chloride monomer unit, and Dissolve 0.15 g of this in nitrobenzene and add 0.5 dl
The reduced viscosity of the solution at 30 ° C. is 0.01 to 20 dl
/ G of vinyl chloride polymer (II) is an essential component, and when an ultrathin section of the molded product is observed using a transmission electron microscope, (a) the molded product It has a sea-island structure in which the copolymer (I) is dispersed in the form of particles, and (b) the dispersed copolymer (I) has a maximum length of 0.1.
Including particles having a size of ~ 15 microns, and (c) when the total area occupied by all particles is 100%,
The total area of the particles shown in (b) is 10% or more. Vinyl chloride resin molded product with excellent heat resistance. 2. The vinyl chloride type polymer having excellent heat resistance according to claim 1, wherein the weight ratio of the copolymer (I) / vinyl chloride type polymer (II) is 0.1 to 50 / 99.9 to 50. Resin molded product. 3. The copolymer (I) comprises a methyl methacrylate unit of 13 to 95% by weight, an aromatic vinyl unit of 1 to 70% by weight, a 6-membered cyclic anhydride unit of 3 to 85% by weight, and a methacrylic acid unit of 0. The vinyl chloride resin molded article having excellent heat resistance according to claim 1, which is a copolymer having a composition of 1 to 20% by weight.