JPH01110549A - Fomable plastisol composition - Google Patents

Abstract

PURPOSE:To obtain the above composition suitable for interior automative trim materials and building materials, having high melt fluidity and excellent low-pressure injection molding properties, by blending a resin consisting of a vinyl chloride-based polymer with a vinyl chloride-ethylene copolymer. CONSTITUTION:(A) 100pts.wt. vinyl chloride-based resin consisting of A1: 60-95 pts.wt. vinyl chloride-based polymer having 0.1-20mum average particle diameter useful for paste obtained by emulsion polymerization or micro-suspension polymerization and A2: 40-5pts.wt. vinyl chloride-ethylene copolymer having 400-2,000 average polymerization degree and 0.5-20wt.% ethylene content is blended with (B) 50-150pts.wt. plasticizer (e.g., dioctyl phthalate), (C) 0.5-15 pts.wt. stabilizer, (D) 0.5-10pts.wt. blowing agent and (E) 2-40pts.wt., preferably 5-30pts.wt. hollow glass beads having 10-200mum diameter, 0.8-0.9g/cc specific gravity and >=1,000kg/cm<2> compression strength.

Description

[Detailed description of the invention] <Field of industrial application> The present invention provides a polyvinyl chloride-based foamable plastisol composition that is particularly excellent in low-pressure injection moldability for injection molding to mold a foam made of a vinyl chloride polymer. Regarding.

<Prior art> Plasticized polyvinyl chloride foam obtained by injection molding a mixture of a soft polyvinyl chloride resin containing a plasticizer and a chemical blowing agent such as azodicarbonamide has excellent texture, chemical resistance, and weather resistance. , is superior to olefin thermoplastic resin foam in terms of flame retardancy, etc., and in recent years, these characteristics have been utilized to develop automobile interior materials,
Up until now, plasticized polyvinyl chloride foams, which have been widely used in the fields of furniture, miscellaneous goods, etc., have been produced by suspension polymerization or bulk polymerization, with an average particle size of 150 um, and are made from general polyvinyl chloride resin and plasticizer. , stabilizers, foaming agents, etc. are mixed, the plasticizer is absorbed into polyvinyl chloride resin using a super mixer, etc., and the resulting powder is dried up. It has been manufactured by injection molding a pellet-shaped compound.

However, the powdered and pelleted compounds of plasticized vinyl chloride resin obtained by the above method have high melt viscosity and low melt fluidity, so high injection pressure and large mold clamping force are required during injection molding. For this reason, it is not possible to insert or outsert parts such as urethane foam whose shape is easily damaged by the pressure during injection, and it is not possible to obtain a foam with uniform cells with a good surface condition and a uniform skin layer. There have been many problems, such as the inability to produce molded products and the difficulty in obtaining molded products with complex shapes.

JP-A No. 59-215880 discloses that a compound containing a polyvinyl chloride resin and a blowing agent has an average particle size of 10 to 20.
It is stated that a foamed vinyl chloride resin composition filled with 0 μm hollow glass beads exhibits good molding processability, and that a molded product that is lightweight and has a good surface condition can be obtained. Lightweight molded products can be obtained due to the action of beads, but as shown in the comparative example, the method of mixing the compound in a super mixer, drying it up, and injection molding using pellets made with an extruder does not melt the product. Since the fluidity is low and the injection pressure is high, a foam with a uniform skin layer cannot be obtained, and there are restrictions on the parts that can be inserted or outsert, making it unsatisfactory.

In addition, for the purpose of obtaining a foam having a uniform skin layer, JP-A-55-75488 discloses that a non-expandable plasticized vinyl chloride-based Ji [composition consisting of pellets, an acrylic resin and/or an ethylene-based A resin composition for injection molding is described in which pellets of a foamable plasticized vinyl chloride resin composition containing a vinyl acetate copolymer are mixed.

However, this method does not solve all of the problems mentioned above, such as low melt flowability and high injection pressure, making it difficult to obtain molded bodies with complex shapes, and restrictions on the parts that can be inserted and outsert. stomach.

<Problems to be solved by the invention> The present invention solves the problems of the prior art as described above,
A small mold clamping force with excellent melt fluidity! To obtain a foamable plastisol composition which can be injection molded at low injection pressure and which can be molded into a foam having a good surface condition and a uniform skin layer using an ordinary injection molding machine.

<Means for Solving the Problems> The present inventors have conducted various studies on flexible polyvinyl chloride resin compositions containing a foaming agent that have high melt fluidity and can be injection molded with low injection pressure, and have developed the present invention. Scattered to completion.

That is, the present invention uses vinyl chloride polymers with an average particle size of 0.1 to 20 μm 60 to 95]! vinyl chloride-based aw consisting of 40 to 5 parts by weight of vinyl chloride-ethylene copolymer
The present invention relates to an expandable plastisol composition characterized in that 50 to 150 parts of a plasticizer, a stabilizer, a blowing agent, and hollow glass beads are blended to 1 part of IOOIIT, and the average particle size of the present invention is 0.1 to 20μ. Vinyl chloride polymers can be produced by emulsion polymerization or microsuspension polymerization using vinyl chloride alone or a mixture of vinyl chloride and other monomers that are copolymerizable with vinyl chloride, and are generally used for pastes. If the average particle diameter is smaller than 0.1 μm, the viscosity of the expandable plastisol composition will increase, which is disadvantageous, and if the average particle diameter is larger than 20 μm, the melt flowability will decrease. Examples of monomers that can undesirably copolymerize with vinyl chloride, such as impairing the effect of increasing the From the viewpoint of product physical properties, it is preferably 10!1% or less.

The vinyl chloride-ethylene copolymer used in the present invention may be produced by a generally known method, and has an average degree of polymerization of 4.
00 to 2000, and the ethylene content is 0.5 to 20% by weight, preferably 0.5 to 10% by weight. If the ethylene content is less than 0.5 Skπ, there will be no improvement in melt fluidity; on the other hand, if the ethylene content is less than 2
゜Xi If it exceeds 11%, the viscosity of the plastisol will increase, which would be disadvantageous. The vinyl chloride-ethylene copolymer is used in a range of 40-5 parts by weight per 60-96 parts by weight.If the amount of the vinyl chloride-ethylene copolymer is less than 5 parts by weight, the effect of improving melt fluidity is Not enough, on the contrary, 40tf
If the amount exceeds the J part, the viscosity of the plastisol increases, which is disadvantageous, and the texture of the resulting foam is also impaired, which is undesirable.As the plasticizer used in the present invention, dioctyl phthalate→
phthalate ester plasticizers represented by , phosphate ester plasticizers represented by tricresyl phosphate, plasticizers such as dioctyl adipate, azelaic ester plasticizers represented by di-2-ethylhexyl azelate, etc. Citrate ester plasticizers represented by tributyl acid, etc.
Glycolic acid ester plasticizers such as butylphthalyl"if zlJ/licorate, trimellitic acid ester plasticizers such as tri-2-ethylhexyl trimellitate, and phthalic acid isomers such as di-2-ethylhexyl terephthalate. Known plasticizers such as polyester plasticizers, polyester plasticizers such as polypropylene adipate, and epoxy plasticizers such as evaporated soybean oil can be used.The blending amount of the plasticizer is as follows: It is used in the range of 50 to 150 parts by weight per 100 parts by weight of the plasticizer.If the amount of plasticizer used is less than 50 parts, the melt fluidity will decrease and the texture of the product will become hard, which is undesirable. If the amount of plasticizer used is less than 1 part of 150 Wf, the product will become too soft (too much) and the surface of the product will become sticky due to bleeding of the plasticizer, which is undesirable.

The stabilizer used in the present invention is added to prevent discoloration, and its use includes 0.5 mSi part of up to about 157 it parts to a total of 100 ffiffiffi parts of the vinyl chloride resin for paste and the vinyl chloride-ethylene copolymer resin. Examples of such stabilizers include complex compounds of barium, lead, cadmium, lead, tin and calcium salts of fatty acids.

The amount used is PVC 8110
The amount is 0.5 parts by weight or more and 10 parts by weight or less with respect to 0 parts by weight. If the amount is less than 0.6 parts by weight, the effect of improving the texture and soft feel of the product will be insufficient, and the effect of attenuating the product will also be insufficient. 1
If the value of 0 is higher than 0, the foaming ratio will be too high and the cell condition of the foam will be too poor, and this will prevent the formation of a uniform skin layer.The foaming agent used is azodicarbonamide or azobis. When used in combination with an azo blowing agent represented by isobutyronitonol, etc., a hydrazide blowing agent represented by dinitro)tpe'so, trihydrazinotriazine, sodium bicarbonate, etc., azodicarbonamide decomposes and remains. A foam that is free from coloration and odor can be obtained.

The hollow glass beads used in the present invention have many effects, such as making the product lighter, acting as a nucleating agent when the blowing agent decomposes, making the foam cells uniform, and increasing the fluidity of the melt. Due to the important additives that it has, the specific gravity is 0.3
~0.9 t/cc, a diameter of 10 to 200 μm, and a compressive strength of 100 Kg/a4 or more, which is close to a perfect sphere without defects.

If the specific gravity is less than 0.8 f/cc, it will break during molding, which is undesirable (on the contrary, if it exceeds 0.9 g/cc, the weight reduction effect will be insufficient. If the diameter is less than 1011 m, it will be effective in increasing melt fluidity. On the other hand, if it exceeds 200 μm, the surface of the product will be rough and the appearance will be impaired, which is undesirable. If the compressive strength is less than 100 Kt/a4, β breakage will occur during molding, which is undesirable. The amount of hollow glass pieces used is vinyl chloride type. Tree 11
2i1 against 1100 Zubu! J 1 copy or more 40 folds FF
I part or less. If it is less than 2 Wi parts, the above-mentioned effect of addition will be insufficient, and conversely, if it is more than 40'g parts, the product surface will be rough, the outer pot will be damaged, and the physical properties of the product will deteriorate, such as tear strength and tensile strength. Undesirable.

In addition to the above-mentioned additives, the foamable plastisol composition of the present invention may optionally contain a vinyl chloride resin for dilution, a thickener, a diluent, a cell conditioner, an antibacterial agent, an ultraviolet absorber, a noodle retardant, and a filler. , colorants, antistatic agents, crosslinking agents, lubricants, etc. are used. Among these, the use of lubricants plays a major role in improving moldability. Examples of the lubricant used for this purpose include metal soaps such as magnesium and aluminum, and the amount used is 5 parts by weight or less per 100 parts by weight of the vinyl chloride resin. If more than 5 parts of plastisol is used, problems such as loss of foaming properties may occur, which is undesirable. Ordinary plastisol kneading equipment such as ink rolls are used for blending and kneading.

The expandable plastisol composition of the present invention can be molded in a paste state that is fluid at room temperature using a conventional injection molding machine.

This may be crushed and molded using a normal injection molding machine.

The foamable plastisol composition of the present invention has good fluidity and can be molded at low injection pressure, so a foam with good surface condition, a uniform skin layer, and excellent texture can be produced in a single injection molding process. It can be obtained with

In addition, it has great advantages such as being able to outsert and insert parts made of materials that easily lose their shape, such as urethane foam, and is used in a wide range of industrial fields such as automobile interior materials, building materials, and miscellaneous goods. .

The present invention will be described in detail with reference to Examples below, but the present invention is not limited to these Examples.
Vinyl chloride resin for paste with an average degree of polymerization of 1700 (
Order Kagaku Kogyo Co., Ltd. Sumirit@)l”XQHA)80
Part by weight and 96% by weight of ethylene obtained by suspension polymerization method
, 95 parts by weight of diundecyl phthalate as a plasticizer, 5 parts by weight of a tin-based stabilizer, and 2 parts of azodicarbonamide as a blowing agent! 2 parts by weight of lubricant and 2 parts by weight of lubricant were mixed in a kneader and foamed under vacuum to obtain plastisol. This plastisol has an average particle size of 60 μm, a specific gravity of 0.6, and a compressive strength of 70.
0Kt15M hollow glass beads 20X! A foamable plastisol composition to be used as a raw material for injection molding was obtained by adding and mixing a certain amount.

This foamable plastisol composition was tested using a BL type viscometer, Todoroki 40-
The viscosity measured at 6 rpm (measurement temperature 25°C) was 2500 cp (centipoise) immediately after preparation at 25°C.
After leaving it for a week under RH condition of 55, 290GC
However, it was a raw material that was easy to handle and had good storage stability.

This foamable plastisol composition was used in a $1'1J-1518 injection molding machine manufactured by Niigata Iron Works as shown in the table below.

(Injection molding conditions) Cs l B 0°C C2100°C Cm 160°C Nozzle 195°C Holding pressure (gauge pressure') 100Ktt/cd Injection time 16 seconds Mold temperature 80°C When operated at the lowest pressure, it reached 20#/ Molding was possible at a very low injection pressure. The PJ resin molded product was a foam with a good cell condition and a skin layer of uniform thickness, and had a good surface condition and an excellent texture.

Examples 2 to 4 Same as Example 1 except that the formulation of the expandable plastisol composition was changed as shown in Table 1 (expandable plastisol compositions were prepared in the same manner as in Example 1, and the injection pressure was Injection molding was carried out in exactly the same manner except for the following: A flat test piece was obtained.The results are shown in Table 1.

Isure's foamable plastisol composition also has a low viscosity and good viscosity stability, and can be injection molded at low pressure without sheet sealing, and the resulting molded product has a skin of uniform thickness. The foam had a good cell condition, a good surface condition, and an excellent texture.

Comparative Examples 1 to 6 Expandable plastisol compositions were prepared in exactly the same manner as in Example 1, except that the formulation of the expandable plastisol composition was changed as shown in Table 1, and the compositions were prepared in the same manner as in Example 1 except for the injection pressure. Except for this, injection molding was carried out in the same manner as above to obtain a plate-shaped molded product. However, in Comparative Example 8, injection molding could not be performed and no molded product could be obtained.

The results are shown in Table @1.

In Comparative Example 1, the injection pressure was high, the uniformity of the skin layer of the molded article was poor, and the condition of the foamed cells and the surface condition were also unsatisfactory. In Comparative Example 2, the plastisol had a large viscosity change, resulting in poor workability, and the foam had insufficient cell and surface conditions, as well as poor texture.

Comparative Example 8 had high plastisol viscosity and poor workability.
High injection pressure was required, and injection molding could not be performed under the same conditions as in Example 1.

In Comparative Example 4, the surface of the foam was sticky and the texture was too soft, and in Comparative Example 5, the injection pressure was high.
The skin layer of the foam had poor uniformity, and the foam cells and surface condition were also insufficient. In Comparative Example 6, the surface of the foam was rough and had poor texture.

Comparative Example 7 A polyvinyl chloride resin UD for paste having an average particle diameter of 120 μm and an average degree of polymerization of 1700 obtained by a hanging parrot polymerization method (Sumirit 05, manufactured by Ninyu Chemical Industry Co., Ltd.) was used.
The same formulation as in Example 1 except that X-17) was used was mixed in a super mixer and extruded in a single screw extruder to obtain pellets. This was injection molded in exactly the same manner as in Example 1 except for the injection pressure, but the injection pressure was too high and no molded product could be obtained.

Comparative Example 8 Using the pellets obtained in Comparative Example 7, Niigata Tekko Shinsei 5N-1
Using a 518 injection molding machine, the following plate-shaped molded product was obtained.

Do not show the results in @1 table.

(Injection molding conditions) C+ 180°C holding pressure (gauge pressure) 150Kq
/adC214G'C Injection time 15 seconds Cs 160°C Mold temperature ao'''C Nozzle 195°C Mold clamping pressure 15 Q TON surface condition was also unsatisfactory.

Claims (3)

[Claims] (1) 60 to 95 parts by weight of vinyl chloride polymer with an average particle size of 0.1 to 20 μm and 4 parts by weight of vinyl chloride-ethylene copolymer
1. A foamable plastisol composition comprising 50 to 150 parts by weight of a plasticizer, a stabilizer, a foaming agent, and hollow glass beads to 100 parts by weight of a vinyl chloride resin consisting of 0 to 5 parts by weight. (2) The expandable plastisol composition according to claim 1, wherein the vinyl chloride polymer is a paste vinyl chloride polymer produced by an emulsion polymerization method or a microsuspension polymerization method. (3) The hollow glass beads have a diameter of 10 to 200 μm
, specific gravity of 0.8 to 0.9 g/cc and compressive strength of 100
kg/cm^2 or more, and the foamable plastisol according to claim 1, wherein the amount is 2 to 40 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the vinyl chloride resin. Composition.