JP2009144090A - Vinyl chloride resin composition and its molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vinyl chloride resin composition and a molded body having a good balance in characteristics of processability, mechanical strength and thermal deformation property. <P>SOLUTION: (1) The vinyl chloride resin composition contains a vinyl chloride resin having a viscosity-average polymerization degree of from 1,300 to 3,800, and 0.5 to 25 mass pts. of a polylactic acid resin with respect to 100 mass pts. of the vinyl chloride resin. (2) The vinyl chloride resin composition contains 0.1 to 10 mass pts. of a thermal stabilizer in the resin composition. (3) A molded body is obtained by molding the vinyl chloride resin composition described in the (1) or (2). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a vinyl chloride resin composition and a molded body thereof, and more particularly to a vinyl chloride resin composition excellent in mechanical strength and thermal deformation and a molded body thereof.

Vinyl chloride resin compositions are widely used in applications such as rain gutters, water and sewage pipes, corrugated plates and window frames, taking advantage of their excellent flame retardancy, weather resistance, and chemical resistance. On the other hand, characteristics such as mechanical strength and heat deformability may be low as compared with general-purpose thermoplastic resins used for the above-mentioned purposes and others.

As the hard vinyl chloride resin used for the above-mentioned purposes, it is common to use a vinyl chloride resin having a viscosity average polymerization degree of less than 1300, and a polymerization degree of 1000 or less for general purposes, from the gelation (melting) behavior during the molding process. Is. When the degree of polymerization is low, the resin composition can be gelled relatively easily during molding, and there is relatively little trouble in terms of moldability when performing molding such as injection molding and profile extrusion. . However, when the degree of polymerization is high, it is difficult to gel easily during the molding process, and the process may be difficult.

Studies are being made to improve mechanical strength and heat deformability without using high-polymerization degree vinyl chloride resin. For example, in order to improve impact strength, a resin composition in which an acrylic impact strength modifier is blended with a hard vinyl chloride resin (see, for example, Patent Document 1), and ABS and MBS are blended with a hard vinyl chloride resin. The resin composition (for example, refer to Patent Document 2) and a resin composition (for example, refer to Patent Document 3) in which chlorinated vinyl chloride is blended with vinyl chloride in order to improve thermal deformation. Proposed. However, since these resin compositions have low material fluidity, there is a case where a high load is applied at the time of molding and a molded product cannot be obtained depending on the shape of the molded product.

In addition, it is known that the bending strength is generally improved by adding a fibrous inorganic filler or the like. However, the addition of the filler causes a decrease in impact strength or a decrease in moldability. There was a case.

Moreover, in order to improve fracture toughness, a resin composition (for example, see Patent Document 4) in which vinyl chlorides having different degrees of polymerization are blended has been proposed. However, although this resin composition has improved processability, the strength may be lowered by using vinyl chloride having a low degree of polymerization.
JP 2000-26552 A Japanese Patent Laid-Open No. 11-60863 JP 2001-11269 A Japanese Patent Laid-Open No. 9-137022

An object of the present invention is to provide a vinyl chloride resin composition having a good balance of processability, mechanical strength, and heat deformability, and a molded product thereof.

As a result of earnest studies on the above problems, the present inventors have added a polylactic acid resin to a vinyl chloride resin composition having a specific degree of polymerization, compared to a conventional hard vinyl chloride resin composition, It was found that processability can be maintained and excellent mechanical strength and heat deformability can be imparted, and the present invention has been completed.

That is, the present invention has the following gist.
(1) Chloride containing a vinyl chloride resin having a viscosity average polymerization degree of 1300 to 3800 and 0.5 to 25 parts by mass of a polylactic acid resin with respect to 100 parts by mass of the vinyl chloride resin. Vinyl resin composition.
(2) The vinyl chloride resin composition according to (1), wherein the resin composition contains 0.1 to 10 parts by mass of a heat stabilizer.
(3) A molded article formed by molding the vinyl chloride resin composition according to (1) or (2).
(4) The molded body has a Charpy impact strength according to JISK-7111 of 9 KJ / m 2 or more, a bending strength according to JISK-7171 of 60 MPa or more, and a Vicat softening temperature according to JISK-7206 of 83. The molded article according to claim 3, which is at least ° C.

ADVANTAGE OF THE INVENTION According to this invention, the vinyl chloride-type resin composition and its molded object which have the characteristics of workability, mechanical strength, and heat-deformability in good balance can be obtained.

The vinyl chloride resin used in the present invention is obtained by means of bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., but preferably considering the initial colorability of the molded product, suspension polymerization is preferable. It is manufactured by. The vinyl chloride resin in the present invention is preferably a homopolymer resin which is a conventionally known vinyl chloride homopolymer, or various conventionally known copolymer resins, but other than these unless it is contrary to the object of the present invention. The vinyl chloride resin may be used. As the copolymer resin, a conventionally known copolymer resin can be used. Preferably, a copolymer resin of vinyl chloride and vinyl esters such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin or the like is used. , Vinyl chloride-butyl acrylate copolymer resins, vinyl chloride-acrylic acid 2-ethylhexyl copolymer resins, etc., vinyl chloride and acrylate esters, vinyl chloride-ethylene copolymer resins, vinyl chloride-propylene copolymer resins, etc. Copolymer of olefins and vinyl chloride-acrylonitrile copolymer resin, more preferably homopolymer resin, vinyl chloride-ethylene copolymer resin, vinyl chloride-vinegar, which is a homopolymer of vinyl chloride A copolymer resin of vinyl copolymer resin. In the copolymer resin, the content of the comonomer is not particularly limited, and can be determined according to the required quality such as moldability.

The viscosity average degree of polymerization of the vinyl chloride resin is in the range of 1300 to 3800, preferably 1300 to 2500. When the viscosity average polymerization degree of the vinyl chloride resin is less than 1300, the molding processability is improved, but the mechanical strength and thermal deformability of the obtained molded article are inferior. The viscosity average degree of polymerization was calculated according to JISK-6720-2 by dissolving 200 mg of resin in 50 ml of nitrobenzene, measuring the specific viscosity of this polymer solution in a constant temperature bath at 30 ° C. using an Ubbelohde viscometer. is there.

The polylactic acid resin in the present invention is not limited by the crystallinity due to the optical purity, so there is no limitation on the ratio of L-form / D-form. Further, the molecular weight of the polylactic acid resin is not limited, and products currently on the market are used without limitation up to those having a weight average molecular weight of about 10,000 to 1,000,000 in terms of standard polystyrene measured by gel permeation chromatography. be able to.

By adding 0.5 to 25 parts by mass of a polylactic acid resin to 100 parts by mass of a vinyl chloride resin having a viscosity average polymerization degree of 1300 to 3800 and 100 parts by mass of the vinyl chloride resin, the resin composition The molded body formed by extrusion molding or injection molding has Charpy impact strength according to JISK-7111 of 9 KJ / m ² or more, bending strength according to JISK-7171 is 60 MPa or more, and conforms to JISK-7206. It is possible to adjust the Vicat softening temperature to 83 ° C. or higher.

In addition to the vinyl chloride resin and the polylactic acid resin, conventionally known additives used for the vinyl chloride resin depending on the purpose are mixed in the resin composition of the present invention. These additives are not particularly limited, but known additives are blended depending on the purpose. For example, lubricants, heat stabilizers, processing aids, reinforcing agents, UV absorbers, antioxidants, antistatic agents, fillers, flame retardants, pigments, initial color improvers, conductivity imparting agents, surface treatment agents, light There are a stabilizer, a fragrance, and the like, but the invention is not particularly limited.

A conventionally well-known thing can be used for the heat stabilizer which can be used for this invention. Among these, it is desirable to use one or more selected from a Ca—Zn-based heat stabilizer, a hydrotalcite-based heat stabilizer, a tin-based heat stabilizer, and a zeolite-based heat stabilizer. The heat stabilizer is used for improving the thermal decomposition during molding, long run property, and appearance of the molded product, and particularly preferably a Ca-Zn system having an excellent balance of molding processability and molded product characteristics. The combined use of a heat stabilizer and a hydrotalcite heat stabilizer is preferred. These heat stabilizers are preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 5.0 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The hydrotalcite-based heat stabilizer is specifically a hydrotalcite compound, more specifically, a complex salt compound composed of magnesium and / or alkali metal and aluminum or zinc, magnesium and aluminum, There is something that has been dehydrated. The hydrotalcite compound may be a natural product or a synthetic product, and the synthesis method of the synthetic product may be a conventionally known method.

The vinyl chloride resin composition in the present invention can be used in combination with the conventional techniques of Patent Documents 1 to 4.

The vinyl chloride resin composition in the present invention is prepared by a conventionally known mixer. For example, a powder compound in which materials are mixed with a Henschel mixer, a super mixer, a ribbon blender, a tumbler, a mazeler, or the like may be used. Using kneaders such as extruders, same-direction twin-screw extruders, conical twin-screw extruders, coniders, planetary gear extruders, plastimeters, roll kneaders, Banbury mixers, etc. It can be kneaded to form a pellet compound. Examples of the molding method of the resin composition include a method of molding by a molding method such as an extrusion molding method, an injection molding method, or a press molding method after any conventionally known production method may be adopted and kneaded. As the molding machine used for the extrusion molding, any conventionally known extruder may be adopted. For example, a single-screw extruder, a different-direction twin-screw extruder, a same-direction twin-screw extruder, a conical twin-screw extruder, etc. Is mentioned. In addition, there are no particular limitations on the mold, the resin temperature, the molding conditions, and the like for molding using the molding machine.

Hereinafter, referring to Table 1, the present invention will be described in detail with reference to examples and comparative examples. These are all illustrative and do not limit the contents of the present invention.

(Raw materials used)
The raw materials used in the examples are as follows.
Vinyl chloride resin TH-1000 (manufactured by Taiyo PVC Co., Ltd .: viscosity average polymerization degree 1000)
TH-1300 (manufactured by Taiyo PVC Co., Ltd .: viscosity average polymerization degree 1300)
TH-2500 (manufactured by Taiyo PVC Co., Ltd .: viscosity average polymerization degree 2500)
TH-3800 (manufactured by Taiyo PVC Co., Ltd .: Viscosity average polymerization degree 3800)
Polylactic acid resin TP4000 (manufactured by Unitika)
H-280 (Mitsui Chemicals)
Processing aid Hydrotalcite-based composite heat stabilizer (Nissan Chemical Industry Co., Ltd .: CP-410A)
Ester lubricant (Riken Vitamin Co., Ltd .: EW-100)
(Mixing method)
Each raw material shown in Table 1 was put into a Henschel mixer, and stirring was continued until the material temperature reached 90 ° C. by utilizing self-heating during stirring from room temperature, and then the mixed powder was cooled.
(Kneading method)
The raw materials mixed as described above were kneaded by a 60 mm single screw extruder (135 to 165 ° C.) to prepare pellets.

(Liquidity)
The fluidity is obtained after kneading by using a flow tester (manufactured by Shimadzu Corporation: CFT-500) by a temperature rising method (temperature rising rate 2 ° C./min, weight 200 kgf, die diameter 0.5 mm × length 10 mm). The viscosity at 175 ° C. is measured using the obtained pellets.

(Kneadability evaluation)
The pellets obtained after kneading are visually measured using a Brabender Plastograph (170 ° C. × 40 rpm × 5 min) and evaluated according to the following criteria.
Excellent: Fully gelled.
Good: Gelled.
Possible: Partially gelled.
Defect: A powdery state.

(Vicat softening point temperature)
The pellets obtained by kneading were kneaded using a φ6 inch two-roll kneader (manufactured by Kansai Roll Co., Ltd .: roll temperature 175 ° C., roll time 5 min) to prepare a roll sheet. Further, a plurality of the sheets were stacked and a press machine (manufactured by Tokai Kikai Co., Ltd .: press temperature 175 ° C., press pressure 120 kgf / cm ² ) was used to obtain a 4 mm thick press sheet. Cutting was performed from the 4 mm thick press sheet so as to form a prism of 15 mm × 15 mm × 4 mm (thickness) to obtain a predetermined test piece. By using a Vicat softening point temperature measuring device (manufactured by Toyo Seiki Co., Ltd .: heating rate 50 ° C./H, load 50 N), this test piece is a method based on 7206.

(Bending strength)
A predetermined test piece was obtained by cutting the 4 mm-thick press sheet used when creating the Vicat softening point temperature measurement test piece into a square column of 80 mm × 10 mm × 4 mm (thickness). Using this test piece, measurement was performed by an autograph AGS-500A (manufactured by Shimadzu Corporation) by a method based on JISK-7171.

(Charpy impact strength)
A predetermined test piece was obtained by cutting the 4 mm-thick press sheet used when creating the Vicat softening point temperature measurement test piece into a square column of 80 mm × 10 mm × 4 mm (thickness). Charpy impact strength was measured by a method based on JISK-7111 using IMPACT TESTER (manufactured by Toyo Seiki Co., Ltd.).

Example 1
100 parts by mass of vinyl chloride resin TH1300, 10 parts by mass of polylactic acid resin TP4000, 3 parts by mass of heat stabilizer CP-410A, and 1 part by mass of WAX EW-100 are weighed and put into a Henschel mixer. The mixture was stirred from room temperature until the material reached 90 ° C., and then the mixed powder was cooled to obtain a mixture of raw materials. Using the 60 mm single screw extruder, pellets (vinyl chloride resin composition) were obtained by controlling the temperature at 135 to 165 ° C. The obtained pellets were kneaded using an oblique axis opposite direction rotating twin screw extruder (manufactured by TOSHIBA MACHINE Co., Ltd .: TEC67), and the molten resin was introduced into the mold so that the mold part temperature was 180 ° C. and the extrusion rate was 85 kg / hr Was extruded to obtain a round pipe (outer diameter 60 mm, wall thickness 1.2 mm). Each characteristic value was evaluated by the method described above. The fluidity, kneadability, Charpy impact strength, and Vicat softening temperature all showed good values.

(Example 2.3)
TH2500 and TH3800, which have a higher viscosity average polymerization degree than the vinyl chloride resin used in Example 1, were used. Other than that was carried out similarly to Example 1, and obtained the resin composition and the molded object (round pipe). In this case, it was confirmed that the Charpy impact strength, the bending strength, and the Vicat softening temperature were further improved while maintaining the fluidity and kneadability at a level where there was no practical problem.

Example 4
Amorphous H280 was used for the polylactic acid resin used in Example 2. Other than that was carried out similarly to Example 2, and obtained the resin composition and the molded object (round pipe). As a result, as in Example 1, good numerical values were obtained for fluidity, kneadability, Charpy impact strength, bending strength, and Vicat softening temperature.

(Example 5.6)
A resin composition and a molded body (round pipe) were obtained in the same manner as in Example 2 except that the addition amount of 10 parts by mass of the polylactic acid resin used in Example 2 was changed to 0.5 parts by mass and 25 parts by mass. Obtained. As a result, as in Example 1, good numerical values were obtained for fluidity, kneadability, Charpy impact strength, bending strength, and Vicat softening temperature.

(Comparative Example 1)
A resin composition and a molded body (round pipe) were obtained in the same manner as in Example 1 except that the vinyl chloride resin used in Example 1 was changed to TH1000 having a low viscosity average polymerization degree. Was bad. Although the fluidity and kneadability were good, the Charpy impact strength was greatly reduced, reaching a level difficult for use as a molded article, and the bending strength was also at a low level.

(Comparative Example 2.3)
In addition to changing the vinyl chloride resin used in Example 1 to TH1000 and TH2500, a resin composition was obtained in the same manner as in Example 1 except that no polylactic acid resin was added. In Comparative Example 2, a molded body (round pipe) could be obtained, but the strength and impact properties were poor. Although the fluidity and kneadability were improved, the Charpy impact strength, bending strength, and Vicat softening temperature were greatly reduced. In Comparative Example 3, a molded body (round pipe) could not be obtained. Further, the fluidity was poor, and the kneadability was also poor, so it was not necessary to prepare a test piece.

(Comparative Example 4)
A resin composition and a molded body (round pipe) were obtained in the same manner as in Example 2 except that 10 parts by mass of the polylactic acid resin used in Example 2 was changed to 40 parts by mass. It was bad. The flowability, kneadability, and Vicat softening point were good, but a significant decrease in Charpy impact strength was observed.

As is apparent from Tables 1 and 2, according to the present invention, it can be seen that a vinyl chloride resin composition having a good balance of processability, mechanical strength, and heat deformability can be easily obtained.

The vinyl chloride resin composition of the present invention can be suitably used for, for example, rain gutters, water and sewage pipes and parts, extrusion molded products such as corrugated plates and window frames, and injection molded products.

Claims (4)

A vinyl chloride resin having a viscosity average polymerization degree of 1300 to 3800, and a polylactic acid resin in an amount of 0.5 to 25 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. Composition. The vinyl chloride resin composition according to claim 1, comprising 0.1 to 10 parts by mass of a heat stabilizer in the resin composition. A molded article formed by molding the vinyl chloride resin composition according to claim 1 or 2. The molded article has a Charpy impact strength according to JISK-7111 of 9 KJ / m 2 or more, a bending strength according to JISK-7171 of 60 MPa or more, and a Vicat softening temperature according to JISK-7206 of 83 ° C. or more. The molded product according to claim 3.