JP3106922B2 - Vinyl chloride resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin composition suitable for use in an extrusion method in which the cross-sectional shape of a molded article changes gradually.

[0002]

2. Description of the Related Art Extrusion molding techniques, such as moldings for automobiles, in which the cross-sectional shape in the longitudinal direction of a long molded product continuously changes are disclosed in Japanese Patent Application Laid-Open Nos. 59-114040 and 4-1.
No. 59154. In these extrusion molding methods, a synthetic rubber or a synthetic resin is extrusion-coated on all or a part of a metal strip, and the shape of the cross section of the coating material changes continuously. It is necessary to select physical properties of a coating material such as a synthetic rubber or a synthetic resin depending on a cross-sectional shape. For example, Japanese Patent Application Laid-Open No. 6-134835 discloses a vinyl chloride-alkyl ester or α -Olefin copolymer is exemplified,
It is difficult to say that the extrusion molding materials have been sufficiently studied.

[0003]

SUMMARY OF THE INVENTION The inventor of the present invention has conducted intensive studies on a resin material which can be extruded according to the shape of the opening even if the shape of the opening of the extrusion die changes continuously. By adding a specific amount of a relatively high-molecular-weight acrylic resin to a soft vinyl chloride resin composition containing a homopolymer as a resin component, it has excellent extruded shape followability, so-called local elongation of the composition at the time of extrusion. The inventors have found that there is no tear and that the extrusion molding is easy, and the present invention has been completed. That is, an object of the present invention is to provide a vinyl chloride resin composition having good shape following properties when used in an extrusion molding method in which the cross-sectional shape of a molded article changes continuously.

[0004]

The gist of the present invention is a vinyl chloride resin composition used in an extrusion molding method for continuously changing the cross-sectional shape of a molded article, wherein the composition is a vinyl chloride resin. 100 parts by weight of homopolymer, plasticizer 20
Acrylic resin 5 having a weight average molecular weight of 1.5 million or more and a content of methyl methacrylate of 60 to 200% by weight and methyl methacrylate content of 60% by weight or more
３０30 parts by weight, and the maximum draft ratio thereof (the vinyl chloride resin composition was subjected to a cylinder temperature of 170 ° C., a shear rate of 1.2 × 10 ² s ⁻¹ and a diameter of 1 mm and a length of 20 mm).
The orifice is extruded, and the extruded filamentous composition is taken up at an increased speed. In this case, the vinyl chloride resin composition has a ratio of the take-up speed immediately before breaking of the filamentous composition to the extrusion speed) of 7 or more.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. The vinyl chloride homopolymer, which is the main resin component of the vinyl chloride resin composition of the present invention, is produced by subjecting vinyl chloride to various methods such as a suspension polymerization method, a bulk polymerization method, a fine suspension polymerization method or an emulsion polymerization method. Everything is used. The average degree of polymerization of the vinyl chloride homopolymer is not particularly limited, but is preferably in the range of 700 to 8000, preferably 1000 to 4000, particularly 1100 to 2500 from the viewpoint of processability and moldability.

[0006] The plasticizer used in the vinyl chloride resin composition of the present invention is not particularly limited as long as it is used for the vinyl chloride resin. For example, di-2-ethylhexyl phthalate, di-n-octyl phthalate, Phthalate ester plasticizers such as diisodecyl phthalate, dibutyl phthalate, and dihexyl phthalate; linear dibasic ester plasticizers such as dioctyl adipate and dioctyl sebacate; trimellitate ester plasticizers; polyester polymer plasticizers; Epoxy-based plasticizers such as epoxidized soybean oil, epoxidized linseed oil, and liquid epoxy resin; and phosphate-based plasticizers such as triphenyl phosphate, trixylyl phosphate, and tricresyl phosphate. Mix and use two or more types.

[0007] The plasticizer sets the vinyl chloride resin composition to a desired hardness. The amount of the plasticizer used varies depending on the type and amount of the vinyl chloride homopolymer or the acrylic resin described below, and on the presence or absence of other additives such as a filler, but based on 100 parts by weight of the vinyl chloride homopolymer. 20 to 200 parts by weight, preferably 25 to 1
It can be appropriately selected from the range of 20 parts by weight.

The acrylic resin blended in the vinyl chloride resin composition is obtained by polymerizing acrylic acid or a derivative thereof, and includes acrylic acid, acrylic acid ester, acrylamide, acrylonitrile, methacrylic acid, methacrylic acid ester and the like. Polymer or copolymer. In particular, in the composition of the present invention, a resin containing 60% by weight or more of methyl methacrylate, preferably 70 to 90% by weight.
And having a weight-average molecular weight in terms of styrene as determined by gel permeation chromatography (GPC) of 1.5 million or more.

The weight average molecular weight of the acrylic resin is usually 5
Less than 100,000 are commercially available, and among them,
It is preferable to use those having a range of 800,000 to 3.5 million. The addition amount of the acrylic resin is 5 to 30 parts by weight, preferably 5 to 30 parts by weight based on 100 parts by weight of the vinyl chloride homopolymer.
It is desirable that the amount be 20 parts by weight, more preferably 8 to 15 parts by weight. If the addition amount of the acrylic resin is less than 5 parts by weight, the elongation during melt softening of the composition is not improved,
On the other hand, when the amount is more than 30 parts by weight, the processability in kneading and pelletizing the composition becomes poor.

By appropriately selecting the molecular weight and the amount of the acrylic resin, the melt viscosity of the vinyl chloride resin composition can be adjusted, and the maximum draft ratio can be set to a desired value. It is possible to improve shape followability and retention during extrusion molding in which the cross-sectional shape changes continuously, and to perform stable extrusion molding without lowering the extrusion speed. Further, in the vinyl chloride resin composition of the present invention,
If necessary, various additives such as stabilizers, fillers, lubricants, antioxidants, ultraviolet absorbers, foaming agents, flame retardants, pigments, impact modifiers, and thermoplastic resins or rubber substances other than those described above are compounded. Is also good.

As the thermoplastic resin and the rubber substance, for example, methyl methacrylate-butadiene-styrene copolymer (MBS), acrylic rubber (AR), butadiene rubber (BR), styrene-butadiene copolymer (SBR),
Acrylonitrile-butadiene copolymer (NBR), acrylonitrile-butadiene-styrene copolymer (AB
S), isoprene rubber (IR), chloroprene rubber (C
R), ethylene-propylene copolymer (EPR), ethylene-vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), nylon and the like.

Examples of the filler include carbon black, calcium carbonate, titanium oxide, talc, aluminum hydroxide, magnesium hydroxide, hydrotalcite,
Clay, silica, white carbon and the like can be mentioned, and the addition of an appropriate amount has the effect of smoothing the kneading and molding of the composition. The amount of the filler is 150 parts by weight or less, preferably 5 to 100 parts by weight, based on 100 parts by weight of the vinyl chloride homopolymer.

In order to produce the vinyl chloride resin composition of the present invention, for example, a vinyl chloride homopolymer, a plasticizer and an acrylic resin and, if necessary, the above-mentioned various additives are uniformly mixed in a temperature range in which the vinyl chloride homopolymer does not deteriorate. Or kneaded. The composition of the present invention is usually used in the form of pellets. The apparatus used for mixing the above-mentioned components is not particularly limited as long as it can be substantially uniformly mixed, and examples thereof include a Henschel mixer, a ribbon blender, and a planetary mixer. For example, an extruder, a roll, a Banbury mixer, a kneader or the like, which can be kneaded under shearing force while heating, is used. As a kneading method, it is also possible to adopt a method in which a resin component and various additives are charged in a first stage by an extruder having a multistage addition port, and a plasticizer is injected in a second stage.

The vinyl chloride resin composition of the present invention produced as described above has a maximum draft ratio of 7 or more, preferably 8 to 50, particularly preferably 8 to 20. When extrusion molding is performed while continuously changing the molding cross section, it has good followability to a change in cross-sectional shape, and an extruded product maintained in a predetermined shape can be obtained. The maximum draft ratio is a value for judging the elongation during melt softening of the composition.
C. and a shear rate of 1.2 × 10 ² s ⁻¹ , extruded from an orifice having a diameter of 1 mm and a length of 20 mm, and withdrawing the extruded filamentous composition while increasing the speed. A value represented by the ratio of the speed and the composition extrusion speed,
That is, it is a value represented by the ratio of the take-up speed to the extrusion speed.

It is essential that the composition of the present invention be used in an extrusion method in which the cross-sectional shape of a molded article changes continuously. The extrusion molding method in which the cross-sectional shape changes continuously refers to an extrusion molding method as shown in the above-mentioned known document, and for example, a resin outflow opening having a cross-sectional shape of a molded product shown in FIG. 1 (front view). This is a molding method using an extruder equipped with an extrusion die 1 comprising a main die 2 having a main die 4 and a movable sub die 3 which changes the shape of the opening along the opening of the main die. In FIG. 1, the sub die 3 moves left and right.

The vinyl chloride resin composition of the present invention is extruded by using the above extruder while changing the shape of an extrusion die. Further, the composition of the present invention may be extrusion-coated on a strip or a line made of metal or hard resin,
Further, a method of performing coextrusion molding with another resin by using a plurality of extruders and combining the resin in or near an extrusion die may be adopted.

[0017]

EXAMPLES Next, the vinyl chloride resin composition of the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples without departing from the gist thereof. The evaluation of the hardness, the maximum draft ratio and the extrudability is as follows.

Hardness: A-type hardness based on JIS K6301 after 10 seconds. Maximum draft ratio: Toyo Seiki Co., Ltd. Capillograph 1B and a melt strength device were used. The take-off speed of the filamentous composition extruded at a constant extrusion speed was measured by a method of sequentially increasing the rotation speed of a pulley provided with a rotation speed adjusting means. Extrusion moldability: The vinyl chloride resin composition was extruded at an extrusion speed of 5 m / min using an extrusion die shown in FIG. The sub die repeatedly moved forward and backward at a speed of 10 mm / sec.

[0019]

Table 1 Molding conditions: Cylinder 1 2 3 Dice Temperature (° C.) 150 155 160 170 ○ Good shape followability and excellent shape retention. △ The shape following property is slightly inferior, but there is no practical problem. × The shape followability is poor, and the shape changes.

Examples 1 to 7, Comparative Examples 1 to 5 Vinyl chloride homopolymer (PVC) of the type and amount (parts by weight) shown in Table 1 and plasticizer (diisononyl phthalate)
And the following acrylic resin, 3 parts by weight of a Ba-Zn composite stabilizer, 1 part by weight of a phosphite-based chelator, 0.3 part by weight of a lubricant, 1 part by weight of an ultraviolet absorber, and 10 parts by weight of calcium carbonate were mixed with a Henschel mixer. did. Next, the mixture was kneaded with a Banbury mixer until the resin temperature reached 165 ° C., formed into a sheet with a mill roll, and then pelletized with a pelletizer. The pellet was used as an evaluation material.

[0021]

Table 2 Acrylic resin Methyl methacrylate / weight average Trademark Manufacturer Alkyl acrylate Molecular weight (% by weight) A METABLEN P530 Mitsubishi Rayon 80-90 / 20-10 3.1 million B Paraloid K125 Rohm & Haas 70-90 / 30-10 200 10,000 C METABLEN P551 Mitsubishi Rayon 80-90 / 20-10 1.45 million

[0022]

[Table 3]

[0023]

According to the vinyl chloride resin composition of the present invention, the desired hardness can be obtained, and the elongation during melt softening is good, that is, the maximum draft ratio is large. Even so, the shape following ability is excellent, and a good molded product corresponding to the shape change can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of an extrusion die.

[Explanation of symbols]

 Reference Signs List 1 extrusion die 2 main die 3 sub die 4 opening

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI B29K 27:06 (58) Investigated field (Int.Cl. ⁷ , DB name) C08L 27/06 B29C 47/00-47/96 C08K 5/10-5/12 C08L 33/12

Claims (6)

(57) [Claims] 1. A vinyl chloride resin composition for use in an extrusion molding method for continuously changing the cross-sectional shape of a molded article, comprising 100 parts by weight of a vinyl chloride homopolymer and 20 to 200 parts by weight of a plasticizer. And methyl methacrylate content 6
5 to 30 parts by weight of an acrylic resin having a weight average molecular weight of 1.5 million or more at 0% by weight or more, and having a maximum draft ratio (a vinyl chloride resin composition having a cylinder temperature of 170 ° C.,
The composition is extruded from an orifice having a diameter of 1 mm and a length of 20 mm at a shear rate of 1.2 × 10 ² s ⁻¹ , and the extruded filamentous composition is taken up at an increased speed. A vinyl chloride resin composition having a ratio of the take-up speed immediately before breaking of the thread-like composition to the extrusion speed at that time) of 7 or more. 2. The weight average molecular weight of the acrylic resin is 180.
The vinyl chloride resin composition according to claim 1, which is in a range of 10,000 to 3.5 million. 3. The vinyl chloride resin composition according to claim 1, wherein the methyl methacrylate content of the acrylic resin is in the range of 70 to 90% by weight. 4. The vinyl chloride resin composition according to claim 1, wherein the maximum draft ratio is in the range of 8 to 50. 5. The vinyl chloride resin composition according to claim 1, wherein the amount of the acrylic resin is in the range of 5 to 20 parts by weight. 6. The method according to claim 1, further comprising a filler.
The vinyl chloride resin composition according to any one of the above items.