JPS5884832A - Manufacture of vinyl chloride-based resin expansion molded product - Google Patents

Abstract

PURPOSE:To obtain titled product of high expansion ratio by charging, into a vinyl chloride-based resin composition heated in an extruder, an organic foaming agent comprising an aliphatic hydrocarbon and an aromatic one compatible with said resin to carry out expansion molding by extrusion. CONSTITUTION:A vinyl chloride-based resin composition is fed to an extruder and heated; into which ca. 1-30pts.wt., based on 100pts.wt. of said resin, of an organic foaming agent comprising (A) at least one sort of an aliphatic (halogenated) hydrocarbon with a boiling point <=90 deg.C (e.g., propane) and (B) an aromatic (halogenated) hydrocarbon compatible with said resin (especially, with a boiling point <=200 deg.C, pref. <=150 deg.C, e.g., benzene) in a weight ratio pref. A/B=100/ 5-30 is charged under pressure. The resulting mixture is homogeneously kneaded in molten state followed by uniformly coaling to a temperature appropriate for expansion, then carrying out an expansion molding by extrusion into the air or a vacuum chamber, thus obtaining the objective product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a vinyl chloride resin foam molded article, and particularly a method for manufacturing a vinyl chloride resin foam molded article having a uniform fine cell structure and a high expansion ratio continuously at a low cost. The present invention provides a method.

Conventionally, the method for manufacturing polyvinyl chloride resin foam moldings has been as follows: (1) A so-called decomposable foaming agent, which becomes a gas upon decomposition, is added to and mixed with vinyl chloride resin, and the mixture is processed using an extrusion molding machine, an injection molding machine, etc. (2) Mix a vinyl chloride resin and a plasticizer to form a paste (plastisol), then mechanically foam the plastisol, or add a decomposable foaming agent to the plastisol. After addition and mixing, the mixture is heated to gel and foam to form the desired product; (3) a mixture containing a decomposable foaming agent;
(4) In the mold, the vinyl chloride resin and the decomposable blowing agent (cooked if necessary: volatile) A known method is to fill the foam with an organic foaming agent, a swelling organic solvent, and a softening agent, heat it under pressure to melt it into a gel, cool it, and then heat it again to foam it. .

However, methods (1) to (3) above cannot produce a rigid or semi-rigid foam; Each method has the disadvantage that it takes a lot of time to obtain the desired results, making the final product expensive.

The present inventors have conducted repeated research on a method for obtaining a vinyl chloride resin foam molded product without such disadvantages, and have first added a heat stabilizer to a vinyl chloride resin, a nucleating agent such as talc, and an acrylic resin. A resin composition containing a decomposable blowing agent such as an azosica-bonamide-based compound is supplied to an extruder, and an organic solvent with a boiling point of 90°C or less is added to the resin composition which is heated and gelled in the extruder. It is only necessary to propose a method of injecting a blowing agent such as an aliphatic hydrocarbon or an aliphatic halogenated hydrocarbon such as propane, butane, pentane, methyl chloride, trichlorofluoromethane, dichlorotetrafluoroethane, etc., and performing extrusion foam molding. Moreover, in order to improve the dispersion in the resin composition, strong mechanical shear is applied to the resin composition, and the resin is melted at a high temperature in order to promote the dissolution of the organic blowing agent into the resin. It is necessary to lower the viscosity, (-) Also, in order to improve the dispersion of the organic blowing agent into the resin composition, it is necessary to lengthen the dispersion mixing zone. Since the resin temperature is raised, it is necessary to uniformly cool the resin to a temperature suitable for foam molding and then extrude it into foam. (e
V) Therefore, the extruder becomes larger and more complicated. As a result, it has been difficult to stably produce a foam molded product having a uniform fine cell structure.

As a result of intensive research by the present inventors to solve such problems, we found that at least one of the above-mentioned aliphatic hydrocarbons and aliphatic ^logenated hydrocarbons as a volatile organic blowing agent,
When used in combination with at least one of aromatic hydrocarbons and aromatic helogenated hydrocarbons that are compatible with vinyl chloride resin, this hydrogen-containing resin can be produced by f? 1.1111 can be easily and efficiently injected into the resin composition in the extruder and is dissolved and dispersed in the resin component.
The interlayer point of ~(IV) is resolved l-11111L
The invention has been completed.

Namely, in the present invention, a vinyl chloride resin composition is supplied in an extrusion manner, and then the resin composition heated in an extruder has (a) a boiling point of 90° C. or lower (preferably 70° C. or lower).
(b) at least one selected from aliphatic hydrocarbons and aliphatic halogenated hydrocarbons, and (b) at least 111 selected from aromatic hydrocarbons and aromatic halogenated hydrocarbons that are compatible with the vinyl chloride resin. The present invention relates to a method for producing a polyvinyl chloride resin foam molded article, which is characterized by injecting a tangled organic foaming agent into the foam and extruding it through melting and mixing.

According to the method of the present invention, the required amount of the mixed organic blowing agent can be easily and uniformly dispersed (dissolved and dispersed) in the heated resin composition in the extruder, resulting in a uniform and fine cell structure. This provides the effect that a polyvinyl chloride resin foam molded article having a high expansion ratio can be manufactured continuously at low cost.

The present invention will be explained in detail below.

The organic blowing agent used in the method of the present invention is composed of at least one of the above-mentioned components (a) and (b), and the aliphatic hydrocarbon having a boiling point of 90°C or less is and propane, butane, imbutane for aliphatic hydrocarbons.

Penta y, neopentane, n-hexitine, isohexitine, n-hebutane, methyl chloride, methylene chloride 1 chloroform, carbon tetrachloride, ethyl chloride, ethylide chloride y,)lichloroethyle V, 1.2-i) chloroethane 1 Totsuchlorofluoromethane, dichlorodifluoromethane, promotrifluoromethane, tetrafluoromethane, dichlorofluoro-a-notane, chlorotrifluoromethane, totsufluoro-a-methane.

Trichlorotrifluoroethane, dichlorite tetrafluoroethane, tetrafluoromethane, chlorobay
Examples include tafluoroethane, hexafluoroethane, chlorodifluoroethane, and difluoroethane. Note that two or more of these may be used in combination.

If an aliphatic hydrocarbon or an aliphatic halogenated hydrocarbon with a boiling point higher than 90°C is used, the special foam will shrink significantly and a foam with a uniform cell structure will not be obtained. In this case, it is necessary to use a component (a) with a boiling point of 90°C or lower,
In particular, it is desirable to use one with a boiling point of 70°C or lower.

On the other hand, the (mouth) ingredients used together with the above (a) ingredient are:

It is necessary that the volume of aromatic solid hydrogen and aromatic halogenated hydrocarbon is compatible with the vinyl chloride resin, and this is particularly suitable under 200 tpi, preferably 150 tpi.
It is desirable that it has a boiling point of ℃ or less, and i is widely used as a parameter for #1 solubility.
P value is 8.5-11. s range is desired, specifically benzene (92), toluene (8°9), xylene (9,0), ethylbenzene (8,8), diedelpeneine (9,4), isoprobilpei V (&8)
sp-cymene (&S), chloropeneine (9,!S)
), dichloropenyne (10,6), )lichlorobenzene (/l, 2), bromobenzene (101), chlorotoluene (9,7), etc. (The numbers in the brackets are all 8P values. The use of these materials is not limited to one type, and two or more types may be used at the same time.

When using an organic blowing agent composed of the above-mentioned (a) component and - (b) component, the usage ratio (#! combined ratio) of component (a) and (b) component 7 and the composition of both of these components. The range of use of organic blowing agents for vinyl chloride resin compositions is determined by the type and degree of polymerization of the raw vinyl chloride resin, the expansion ratio and cell structure of the intended foamed product, etc. The components are mainly foaming caused by vaporization when the mixture melted and kneaded in the extruder is discharged under atmospheric pressure, homogenization of cells formed by foaming, and lowering the resin temperature of the foam due to latent heat of evaporation. Component (B) mainly serves to reduce and stabilize the injection pressure when injecting the organic blowing agent into the resin composition in the extruder, and to disperse the organic blowing agent by lowering the resin melt viscosity in the extruder. Since it works to increase efficiency, the mixing ratio of component (a) and component (b) is preferably 1 to 50 parts by weight per 100 parts by weight of component (a). It is desirable that the amount is 1 to 30 parts by weight, and 1 to 30 parts by weight of the foaming agent consisting of component (a) and component 1) is used per 100 parts by weight of the vinyl chloride resin composition. Brilliant.

In the method of the present invention, generally, a raw material vinyl chloride resin composition is first prepared in advance using a mixer such as a super mixer, and this is fed to an extruder, and then the resin composition is heated in the extruder. Ingredient (a) mentioned above and 1
A predetermined amount of an organic blowing agent consisting of the following ingredients is press-fitted from the middle of the cylinder, and the press-fitted organic blowing agent is uniformly dispersed (dissolved and dispersed) in the resin composition in the melt mixing zone in the sitter, and then foamed. This is carried out by uniformly cooling the resin composition to a suitable temperature and extruding it into the atmosphere or into a reduced pressure section to form foam molding.

The organic blowing agent may be press-injected at any time as long as it does not pack the organic blowing agent into the resin composition supply port and thereby prevent the resin composition from being bitten into the resin composition. This is often done when the resin IIA is in a semi-gelled state or completely gelled state,
In either of these states, the organic blowing agent is easily and uniformly dispersed in the resin composition, resulting in a molded article having a uniform cell structure and a high expansion ratio.

The raw material vinyl chloride resin composition used in the method of the present invention is a mixture of vinyl chloride resin as a main ingredient and various necessary ingredients or additives. For example, from the standpoint of obtaining a better foam molded product, vinyl chloride resin 100
0.011 parts or more of a cell confinement aid made from a pyrolytic foaming side 1 and a high-melting point fine powder substance for adjusting the cell structure uniformly and finely during foam molding per 1 part;
and acrylic resin and/or styrene to promote or adjust the gelation of vinyl chloride resin, - increase the melt viscosity of the resin or adjust it to an appropriate viscosity, and prevent cell coalescence or shrinkage at high temperatures. System resin 0.5~
301 parts by amount and, if necessary, various additives conventionally added to vinyl chloride resins (stabilizers, lubricants, fillers, etc.) in amounts that do not impair the purpose or effect of the present invention.

Vinyl chloride resins are not limited to polyvinyl chloride,
In various copolymers mainly composed of vinyl chloride, examples of comonomers that can be copolymerized with vinyl chloride include vinyl acetate 11
．． vinylidene chloride, acturic acid and its esters, methacryl 6H1 and its esters, acrylonitrile,
Metacriminitril.

Examples include one or more types of maleic acid and its esters or anhydrides, fumaric acid and its esters, olefins such as ethylene and propylene, and vinyl ethers. Examples of polymers having good miscibility with vinyl resins include polyvinyl chloride, lyso-y, ethylene-vinyl acetate copolymer, AB8 resin, M11B resin, chlorinated polyethene, and synthetic rubbers such as N11%88H.

Actul resins are those that can uniformly promote the gelation of vinyl chloride resins, increase resin viscosity appropriately, provide rubber elasticity, and improve the tensile strength or elongation rate of vinyl chloride resins at high temperatures. .

That is, 2 as a 0.1f/100-chloroform solution.
The reduced viscosity measured at 0°C is 3.0 dl/7 or more,
Select and use an acrylic resin with a high degree of polymerization that is larger than the raw material vinyl chloride-based polymer used and has good compatibility.2
This preferably includes methyl methacrylate polymers or copolymers mainly composed of methyl methacrylate, such as copolymers of methyl methacrylate and acrylic esters, and copolymers copolymerizable with these. Examples include polymers.

In addition, similar to the aforementioned acrylic resins, styrene resins have good compatibility with vinyl chloride resins, increasing the melt viscosity of the resin when melting the resin composition and imparting rubber elasticity. One that can improve the tensile strength or elongation rate of the resin at high temperatures and prevent coalescence or shrinkage of cells during foaming to obtain the desired high-foaming molded product, that is, 0.1/100g11/ Reduced viscosity measured as a chloroform solution at 20°C is 3.0 d.
It is desirable to select and use one with a high degree of polymerization that is l/7 or more and has good compatibility with the vinyl chloride resin used.
Copolymers of 9 and/or monomers copolymerizable with these (acrylic esters, methacrylic esters, maleic esters, fumaric esters) are preferred. Note that, if the polymerization degree of the vinyl chloride resin used as the main resin is high, it is desirable to use a styrene resin having a high polymerization degree corresponding to the high polymerization degree of the vinyl chloride resin used as the main resin.

Furthermore, as thermally decomposable blowing agents, azo blowing agents such as azodicarbonamide, azobisisobutyronitrile, diazoaminobenzone, diethyl azodicarboxylate, diisopropyla, zodicarpooxylate, and diazoaminobenzone; Nitroso blowing agents such as N,N'-dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, penynesulfonyl hydrazide, toluenesulfonyl hydrazide, 3,3'-disulfone hydrazide phenylsulfone,
Toluene disulfonyl hydrazone, thiobis(benzenesulfonyl hydrazide), toluenesulfonyl azide,
Toluenesulfonyl semicarno<diV, 4.4'-t+
Examples include sulfonyl hydrazide blowing agents such as νbis (benzenesulfonyl hydrazide), sodium bicarbonate, and the like.

In addition, high melting point fine powder substances include inorganic substances such as calcium carbonate, talc, pararam sulfate, fumed silica, titanium oxide, clay, aluminum oxide, bentonite, diatomaceous earth, and citric acid, tartaric acid, oxalic acid, etc. Examples include combinations of organic acids or acids such as boric acid and sodium, potassium, or ammonium bicarbonates or carbonates.

By extrusion foam molding according to the method of the present invention described above, a polyvinyl chloride resin foam molded product having a uniform fine cell structure in various shapes such as plate, sheet, rod, and tube shape and having a high expansion ratio can be continuously produced. can be manufactured at low cost.

Next, specific examples will be given.

Example (Experiment Al~16) Vinyl chloride resin 100 with various degrees of polymerization (as shown in the table)
Parts by weight, 2 parts by weight of lead-based stabilizer, 1M part by calcium stearate, 3 parts by weight of talc, Cellmic 133 (manufactured by Sankyo Kasei, Azocica-bonamide-based compound, decomposition temperature 130
-180℃) α5 parts by weight, and acrylic polymer (
Copolymer consisting of 80% by weight of methyl methacrylate and 20% by weight of n-butyl acrylate, reduced viscosity 11.5 t
11/f) 10 parts by weight were mixed in a super mixer.

Each resin composition thus obtained was extruded and foam-molded into a plate shape using the following two extruders connected together. However, the type and injection amount of the organic blowing agent were as shown in the table.

[Extruder]

The first extruder has a diameter of 50mm and L/D-30, and the V9 under of this extruder is equipped with a blowing agent injection hole through which the organic blowing agent can be injected using a dual plunger pump. It is designed like this. The second extruder has a diameter of 65 mm,
L/D-28, which is connected to the tip of the first extruder. And at the tip of this second extruder, 4mT
A 450mL dice is attached.

[No. 1 - extruder temperature conditions, etc.]

Cylinder temperature: 10 90-%-120℃20 1
20~180℃ sa iso~170℃ 40 150~170℃ Temperature of connecting pipe: 150~170℃ Organic blowing agent injection pressure 2 Listed in table Rotation speed: sO rotation (S2 extruder temperature conditions, etc.) Cylinder 1 temperature :10 145-160℃20 135
~150℃ 30 122! -140℃ Die temperature = 120~135℃ Rotation speed: 15
- Pressure crab of 18-turn die When the density (IP/d) and cell state of the plate-shaped foam obtained by extrusion foam molding under the conditions above those listed in the table were investigated, the results were as shown in Table 1. Met.

(Cell Condition Judgment Criteria) M: It has a fine uniform cell structure with a cell diameter of 1000 m or less, and has an excellent appearance.

1: Cell diameter is 1000. am or more, and the cells are coarse and non-uniform.

[Abbreviations used in the table]

TCP'M:) Lichloromonofluoromethane EB:
Ethylbenzene λB Niamylbenzene MLO: Methyl chloride MNC: Methylene chloride DPB Nidipropylbenzene TCB: 1,2.4-trichlorobenzene DPN:
Diventene

Claims (1)

[Claims] 1. A vinyl chloride resin composition is supplied in an extrusion manner, and then, in the resin composition heated in this extruder, (a) aliphatic hydrocarbons and fats having a boiling point of 90°C or less are added. At least one type selected from aromatic hydrogenated hydrocarbons and aromatic hydrogenated hydrocarbons, which are compatible with vinyl chloride resins. The organic blowing agent is injected and extruded through melt kneading and JI extrusion.
IP111I! Method 1 for producing a polyvinyl chloride resin foam molded article, characterized in that the (CI) component has a boiling point of 200°C or lower, preferably 1
The manufacturing method 3 according to claim 1, which is 50° C. or lower, the combined ratio of the component (a) and the component (b) is (a)
The manufacturing method according to claim 111, characterized in that (b) 1 to 401 parts by weight of component per 100 parts by weight of component, preferably 5 to 30 parts by weight.