JPH06145452A - Hard vinyl chloride resin composition - Google Patents

Abstract

(57) [Summary] [Constitution] 100 parts by weight of polyvinyl chloride resin is dehydrated from one or more dicarboxylic acids selected from aliphatic dicarboxylic acids, alicyclic dicarboxylic acids and aromatic dicarboxylic acids, and aliphatic polyols. Polyester obtained by condensation (number average molecular weight 1000 to 10000), 0.1 ~ as a processing aid
A hard vinyl chloride resin composition containing 20 parts by weight. [Effect] When processing polyvinyl chloride-based resin, it has both a gelation-promoting effect and a lubricant effect, and also improves the flowability during molding, prevents flow burns, improves the surface properties of molded products, and further reduces sink marks. It has the effect of prevention.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard vinyl chloride resin composition containing a polyester as a processing aid for molding a polyvinyl chloride resin.

[0002]

2. Description of the Related Art Polyvinyl chloride resins have excellent physical and chemical properties and are therefore hard products such as films, sheets, bottles, pipes and various molded products, or soft products such as floor materials and wire coatings. Is widely used in the field of application.

Polyvinyl chloride resin (PVC) is widely blended with a gelation accelerator for the purpose of promoting melting of the resin during processing and improving moldability. Further, in order to improve the dynamic thermal stability of the polyvinyl chloride resin and reduce the strain during molding, an external lubricant, an internal lubricant or a filler is also blended.

The lubricant is intended to reduce interactions between the PVC primary particles and the metal surface and between the primary particles. On the other hand, the gelation accelerator is intended to further strengthen the interaction between the PVC primary particles and the metal surface and between the primary particles to promote kneading. Therefore, the interaction is maintained even after the gelation is completed, and the melting torque is increased.

For this reason, for the purpose of improving the processability, a processing aid having an effect of promoting the kneading until gelling and then weakening the interaction between the primary particles of PVC and the metal surface and the interaction between the primary particles is used. It has been demanded.

The conventional gelling accelerator is one of the important factors necessary for the molding process of polyvinyl chloride resin, because the interaction between the primary particles and the metal surface and between the primary particles is too important. There is no or little if any.
In addition, since the gelling promoter having a slipping property places emphasis on slipperiness, the gelling promoting effect is small.

On the other hand, the lubricant has a different effect from that of the gelation accelerator, reduces the interaction between the primary particles and the metal surface and the interaction between the primary particles, and also reduces the interaction between them. Friction between the primary particles of the vinyl chloride resin and the metal surface or between the primary particles can be suppressed to improve the dynamic thermal stability of the polyvinyl chloride resin.

[0008]

DISCLOSURE OF THE INVENTION The present invention has the contradictory effects of the above-mentioned gelation accelerator and lubricant at the same time, improves the workability at the time of injection and extrusion molding, prevents fluid burning, and prevents the surface of a molded article. The purpose is to use a processing aid that is effective in improving the properties and preventing sink marks.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have investigated a processing aid having the contradictory effects of the above-mentioned gelation accelerator and lubricant, and as a result, found that aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, aromatic The present invention has been completed by blending one or more dicarboxylic acids selected from the group dicarboxylic acids and a polyester (number average molecular weight of 1,000 to 10,000) obtained from an aliphatic polyol into a polyvinyl chloride resin.

That is, the present invention has both a gelation accelerating effect and a lubricant effect at the time of processing a polyvinyl chloride resin, and further, improves the flowability at the time of molding, prevents flow and burn,
A processing aid that is effective in improving the surface properties of molded products and preventing sink marks is added.

The polyester according to the present invention is synthesized by dehydrating and condensing an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid, an aromatic dicarboxylic acid and an aliphatic polyol.

Examples of the dicarfonic acid used in the present invention include oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, fumaric acid, dimer acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and trimellitic acid. Examples thereof include acids and their anhydrides.

Examples of the aliphatic polyol include ethylene glycol, propylene glycol, 1,3 butanediol, 1,4 butanediol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane and pentaerythritol.

As the polyester polymerization method, a usual method can be used. For example, a method of performing a transesterification reaction of a dimethyl ester of a dicarboxylic acid and an aliphatic polyol to distill off methanol, and then gradually reducing the pressure to perform polycondensation under high vacuum, or an esterification reaction of the dicarboxylic acid and the aliphatic polyol. After distilling off the produced water, the pressure is gradually reduced and polycondensation is performed under high vacuum. As the transesterification catalyst, calcium acetate, zinc acetate and the like can be used, and as the polycondensation catalyst, known ones such as dibutyl tin oxide and titanium tetrabutoxy can be used. However, various conditions such as the polymerization method and the catalyst are not limited to the above examples.

The polyester according to the present invention preferably has a number average molecular weight determined by gel permeation chromatography in the range of 10,000 to 10,000. When the number average molecular weight is less than 1,000, the gelling-promoting effect (performance similar to that of a plasticizer) is obtained, but the lubricant effect is very little or not at all. On the other hand, when the number average molecular weight is more than 10,000, it has a lubricant effect and little or no gelation promoting effect.

The hard vinyl chloride resin composition of the present invention comprises
Conventionally known lubricants, processing aids, etc., such as higher fatty acids or metal salts thereof, higher alcohols, monoglycerides, waxes, etc., can be further added.

The hard vinyl chloride resin composition obtained as described above is excellent in improving the flowability in extrusion molding and injection molding, preventing flow burn, improving the surface property of the molded product, and preventing sink mark. . Also in calendar molding, it is excellent in improving gelation property, preventing flow marks, preventing plate-out and the like.

[0018]

EXAMPLES The present invention will be described more specifically with reference to the following examples.

Table 1 shows polyesters obtained by reacting phthalic anhydride, maleic anhydride, propylene glycol, ethylene glycol, dipropylene glycol, and trimethylolpropane in the molar ratios shown in Table 1 below.

[0020]

[Table 1]

Then, each polyester shown in Table 1 was blended with polyvinyl chloride resin as a processing aid (Table 2), melted and kneaded by a Henschel mixer, and then injection molding machine IS5.
Cylinder temperature 180 ℃, mold temperature 50 ℃ and injection pressure (gauge pressure) 80Kg by 5EPN type (trade name, manufactured by Toshiba Machine).
Injection molding was performed under the condition of / cm ² , and the following spiral flow test was performed to evaluate the flowability.

A test piece for measuring physical properties was obtained under the same conditions as described above. The test pieces were evaluated for surface properties (silva streak), sink marks, burns, etc. as shown below, and the results are shown in Table 3.

[0023]

[Table 2]

Spiral flow test: The flow distance is measured by injecting in a spiral flow mold under the same conditions. The larger this value is, the better the flowability is.

Tensile strength, elongation: JIS K 7
113

Flexural strength, flexural modulus: JIS K 7
203

Izod impact strength (notched): J
IS K 7110

Surface property (Silva streak): Surface appearance of square shaped plate (10 cm in length and width, 3 mm in thickness)

Sink, burn: bar-shaped molded product (width
12mm, thickness 6mm) surface appearance

[0030]

[Table 3]

[0031]

As is clear from the test results, all of the examples of the present invention are excellent in spiral flow flowability and excellent in surface properties, sink marks, burns and physical properties of molded articles. I understand. Therefore, the hard vinyl chloride resin composition of the present invention is suitably used as an injection molded product such as a housing, a pipe joint, a valve, and the like, an industrial plate, a pipe, a gutter, an extrusion molded product such as a window frame.

Claims (1)

[Claims] 1. One or more dicarboxylic acids selected from aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids per 100 parts by weight of polyvinyl chloride resin,
Polyester (number average molecular weight of 10,000 to 10,000) obtained by dehydration condensation from an aliphatic polyol is used as a processing aid.
A hard vinyl chloride resin composition, characterized in that 0.1 to 20 parts by weight is added.