JP2001150510A - Adaptor in extrusion molding apparatus, extrusion molding apparatus, method of manufacturing for thermoplastic resin sheet, method of manufacturing for thermoplastic resin foamed sheet, method of manufacturing for formable composite sheet and method of manufacturing for composite foamed sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adaptor constituted so as to form a flow mark to as near the end part as possible of a molded article, an extrusion molding apparatus using the same, a method of manufacturing for a thermoplastic resin sheet using the extrusion molding apparatus and a method of manufacturing for a thermoplastic resin foamed sheet. SOLUTION: The adaptor 4 in an extrusion molding apparatus of a thermoplastic resin is constituted so that the interval from the inner surface of the adaptor to the central part of the screw head of adjacent screws is set to 0.1-10% of the interval R from the inner surface of the adaptor to the inner surface opposed thereto and the position of the flow mark 7 of a molded article generated by the stagnation of the thermoplastic resin in the space in front of the screw head is formed at the position corresponding to the end part of a die. The extrusion molding apparatus is equipped with the adaptor 4, a twin-screw extruder 2 and a die 3. A method of manufacturing for a thermoplastic resin sheet using the extrusion molding apparatus and a method of manufacturing for a thermoplastic resin foamed sheet are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin molding material such as a polyolefin resin, for example, in the form of a sheet.
An adapter in an extruder for extruding,
The present invention relates to a method for producing a thermoplastic resin sheet, a method for producing a thermoplastic resin foam sheet, a method for producing a foamable composite sheet, and a method for producing a composite foam sheet using the extrusion molding apparatus.

[0002]

2. Description of the Related Art FIGS. 9 (a) and 9 (b) show a foamable resin composition obtained by adding a thermal decomposition type chemical foaming agent to a thermoplastic resin and kneading the mixture.
1 shows an outline of a conventional extrusion molding apparatus for extruding into a sheet shape through a T-die 3 by an extruder 2. In the conventional extrusion molding of a thermoplastic resin, as shown in FIG. 9, a twin screw 1 arranged in a barrel 1 of an extruder 2 is used.
Resin stays in the space before the head of No. 3 and, in many cases, so-called flow marks 7 appear on both sides of the foamed sheet 8 which is an extruded product due to the stay resin 5.

[0003] More specifically, when the foamable sheet 8 is extruded from the T-die 3 by an extruder in which an adapter 14 is provided between the barrel 1 of the extruder 2 and the T-die mounting bracket 6, FIG. As shown in b), one having a flow mark 7 near the center of the width was obtained.

Conventionally, in order to suppress the occurrence of this phenomenon, Japanese Patent Application Laid-Open Nos. 56-150526 and 4-27
As disclosed in JP-A-6420 and JP-A-4-339632, measures have been proposed such as modifying a breaker or an adapter provided in an extruder or using a gear pump for adjusting a flow rate fluctuation. .

[0005]

However, according to the above-described method of modifying a breaker or an adapter, the flow mark cannot be completely eliminated from a molded product obtained by extrusion molding. When the resulting foamable composite sheet was foamed, the flow marks generated by the resin staying could not be completely erased, resulting in a decrease in the strength of the product and an adverse effect such as poor appearance.

Although it is possible to eliminate the flow mark by using a gear pump, it is difficult to stabilize the flow rate of the molten resin, and the flow mark still remains slightly.

[0007] When a product is manufactured except for both side portions including the flow mark, the effective width of the product is narrow and the yield is low, so that there is a problem in cost, and it is difficult to manufacture a wide product.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems in extruding a thermoplastic resin by an extrusion molding apparatus having the above-mentioned screw. As formed in the part, such that a wide product with high production efficiency can be obtained, an adapter in an extrusion molding apparatus and its extrusion molding apparatus, and a method for producing a thermoplastic resin sheet using the extrusion molding apparatus, An object of the present invention is to provide a method for producing a thermoplastic resin foam sheet. Still another object of the present invention is to provide a method for producing a foamable composite sheet capable of controlling the position of a flow mark and controlling the cell shape of a foam by using the extrusion molding apparatus, and using the foamable composite sheet. An object of the present invention is to provide a method for producing a composite foam sheet.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object.
An adapter in a thermoplastic resin extrusion molding apparatus including a twin screw extruder, an adapter, and a die, wherein an interval from an inner surface of the adapter to a center portion of a screw head of an adjacent screw is opposed to the inner surface of the adapter. 0.1 to 10% of the distance to the inner surface of the die, and the position of the flow mark of the molded product caused by the stagnation of the thermoplastic resin in the space ahead of the screw head corresponds to the end of the die. The present invention provides an adapter in an extruder which is adapted to be formed at a position where the extruder is formed.

According to a second aspect of the present invention, in a thermoplastic resin extrusion molding apparatus provided with a twin screw extruder, an adapter and a die, a distance from an inner surface of an adapter to a center of a screw head of an adjacent screw is provided. But,
0.1 to 10 of the distance between the opposite inner surfaces of the adapter
%, And the position of the flow mark of the molded product caused by the stagnation of the thermoplastic resin at the tip of the screw head is formed at a position corresponding to both sides of the die. An extrusion molding apparatus is provided. According to a third aspect of the present invention, a thermoplastic resin is extruded into a sheet using the extrusion molding apparatus according to the second aspect, and flow marks formed on both sides of the obtained molded article are formed on both sides of the molded article. Provided is a method for producing a thermoplastic resin sheet in which a part is cut off and the remainder is a product.

According to a fourth aspect of the present invention, a foamable resin composition containing a thermoplastic resin and a thermally decomposable chemical foaming agent is formed into a sheet by using an extrusion molding apparatus according to the second aspect. Then, the obtained foamable sheet is foamed, flow marks generated on both sides of the sheet are cut off together with both sides of the sheet, and a method for producing a thermoplastic resin foam sheet with the remaining part as a product is provided.

The invention according to claim 5 provides a foamable resin composition containing a modified resin obtained by reacting a polyolefin resin with a modifying monomer and a pyrolytic chemical foaming agent. A sheet-like material having a shape capable of suppressing foaming in an in-plane direction when the sheet is heated and foamed on at least one surface of the obtained foamable sheet using the extrusion molding apparatus described in the above. And a method for producing an expandable composite sheet. The invention according to claim 6 provides a method for producing a composite foamed sheet in which the foamable composite sheet obtained by the method according to claim 5 is heated and foamed.

Hereinafter, the present invention will be described in more detail. First, a method of manufacturing a thermoplastic resin sheet, a method of manufacturing a thermoplastic resin foam sheet, a method of manufacturing an expandable composite sheet, and a method of manufacturing a composite foam sheet using the expandable composite sheet together with an outline of an extrusion molding apparatus Raw materials used in the invention will be described, and then details of the adapter and the extrusion apparatus will be described.

In the present invention, the twin-screw extruder provided in the extrusion molding apparatus is not particularly limited as long as the twin-screw is attached. It may be a directional rotary extruder.
The die is not limited to the T die, but may be a pipe die, an inflation die, a spiral die, or the like. The cross-sectional shape of the resin flow path of the adapter is not particularly limited. However, in general, in order to be a resin flow path that can be extruded, the cross section in the length direction of the flow path has a curved shape. What is formed is preferred. However, as described later, the specified distance must be maintained between the inner surface of the adapter and the adjacent screw.

In order to produce a foamed thermoplastic resin sheet by using the extrusion molding apparatus of the present invention by the method according to the present invention, a thermoplastic resin such as a polyolefin resin is usually added to a thermally decomposable chemical foaming agent. Is added and kneaded, and the obtained foamable resin composition is shaped into a sheet through a T-die by a twin screw extruder of an extrusion molding apparatus, and the obtained foamable sheet is heated to decompose the foaming agent. It is manufactured through a process of foaming. The thermoplastic resin used is not particularly limited, but a polyolefin-based resin is preferably used from the viewpoint of excellent chemical resistance, flexibility and elasticity, and cost.

Further, in the method for producing an expandable composite sheet according to claim 5, the polyolefin resin is modified by reacting it with a modifying monomer, and the resulting modified resin and a thermally decomposable chemical foaming agent are contained. A foamable resin composition, usually a foamable resin composition obtained by kneading a modified resin and a thermal decomposition type chemical foaming agent, is supplied to the extrusion molding apparatus of the present invention.

Throughout this specification, "in-plane direction" means any direction in the sheet surface of the foamable sheet, including the length direction and the width direction. In addition, the term “sheet” does not refer to a form in a strict sense based on thickness,
It includes a relatively thin film usually called a film and a relatively thick film usually called a plate material.

The polyolefin as the main component of the polyolefin resin used in the invention of claim 5 is a homopolymer of an olefinic monomer or a copolymer of a main component olefinic monomer and another monomer. Although not limited, for example, polyethylene such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, homo-type polypropylene, random-type polypropylene, polypropylene such as block-type polypropylene, polybutene, ethylene-propylene copolymer Copolymers containing ethylene as a main component such as a copolymer, an ethylene-propylene-diene terpolymer, an ethylene-butene copolymer, an ethylene-vinyl acetate copolymer, and an ethylene- (meth) acrylate copolymer. Etc. are also exemplified. It may be two or more of a combination of.

In the polyolefin resin, if the proportion of the polyolefin is 70 to 100% by weight,
For example, polystyrene, styrene-based elastomer, etc.
Resins other than the specified polyolefin may be blended. If the proportion of polyolefin in the polyolefin resin is less than 70% by weight, not only the characteristics of polyolefin such as light weight, chemical resistance, flexibility and elasticity cannot be exhibited, but also it is difficult to secure the melt viscosity required for foaming. This is not preferable because it may result in

The modifying monomer used in the invention of claim 5 is a compound having two or more functional groups capable of radical reaction in the molecule. Examples of the functional group include an oxime group, a maleimide group, a vinyl group, an allyl group, and a (meth) acryl group. The modifying monomer is preferably a dioxime compound, a bismaleimide compound,
Divinylbenzene, allyl-based polyfunctional monomer, (meth)
Acrylic polyfunctional monomer. Further, the modifying monomer may be a cyclic compound having two or more ketone groups in the molecule, such as a quinone compound.

Among the above modifying monomers, compounds having two oxime groups in the molecule, that is, dioxime compounds have a structure in which an oxime group or its hydrogen atom is substituted by another atomic group (mainly a hydrocarbon group). It is a compound having two in the molecule, for example, p-quinonedioxime and p, p-dibenzoylquinonedioxime. The dioxime compounds may be used in combination of two or more.

Among the above modifying monomers, bismaleimide compounds having two maleimide structures in the molecule include, for example, N, N'-p-phenylenebismaleimide,
N, N'-m-phenylene bismaleimide and diphenylmethane bismaleimide are exemplified. Bismaleimide compounds can also be used in combination of two or more. Also, polymaleimides having two or more maleimide structures in the molecule are included in the category of bismaleimide compounds because they have the same effect.

Among the above-mentioned modifying monomers, the compound having two vinyl groups in the molecule, that is, the divinyl compound includes, for example, divinylbenne, etc., and the two vinyl groups are in any of the ortho, meta and para positions. It may be.

Among the above modifying monomers, compounds having two or more allyl groups in the molecule, ie, allyl-based polyfunctional monomers, include, for example, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and diallyl chloridendate. Is exemplified. The allylic polyfunctional monomer may be used in combination of two or more.

Among the above modifying monomers, compounds having two or more (meth) acryl groups in the molecule, that is, as the (meth) acrylic polyfunctional monomer, compounds having 2 to 4 (meth) acryloyloxy groups Is mentioned. Examples of the (meth) acrylic bifunctional monomer having two (meth) acryloyloxy groups include alkanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and polyethylene glycol di (meth). )
Acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, ethylene glycol adduct of bisphenol A di (meth) acrylate, propylene glycol adduct of bisphenol A Di (meth) acrylate is exemplified.

The (meth) acrylic trifunctional monomer having three (meth) acryloyloxy groups includes trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and trimethylolpropane ethylene oxide-added tri (meth) acrylate. A) acrylate, glycerin propylene oxide-added tri (meth) acrylate, and tris (meth) acryloyloxyethyl phosphate. Examples of (meth) acrylic tetrafunctional monomers having four (meth) acryloyloxy groups include pentaerythritol tetra (meth)
Acrylates and ditrimethylolpropanetetra (meth) acrylate are exemplified.

Among the above modifying monomers, a typical example of a cyclic compound having two or more ketone groups in a molecule is a quinone compound. Examples of the quinone compound include hydroquinone and p-
Benzoquinone and tetrachloro-p-benzoquinone are exemplified.

The amount of the modifying monomer may be appropriately selected according to the type of the monomer, but is generally 0.05 to 5 parts by weight, preferably 0.2 to 5 parts by weight, per 100 parts by weight of the polyolefin resin. ~ 2 parts by weight. If the amount of the modifying monomer is less than 0.05 part by weight, it is difficult to obtain a melt viscosity required for foaming. If the compounding amount exceeds 5 parts by weight, the degree of crosslinking becomes too high, extrudability deteriorates (for example, high load is applied or melt fracture occurs), and a foaming agent to be added later is added to the resin composition. It cannot be kneaded uniformly inside, and the gel fraction is unnecessarily increased too much, which may impair the recyclability. In addition, the foaming pressure at the time of heat foaming becomes too high later, and a sheet having a low tensile strength may not be used as a sheet-like material for suppressing in-plane foaming.

In the method of the present invention, an organic peroxide may be used together with the modifying monomer. In particular, when a divinyl compound or an allyl-based polyfunctional monomer is used as the modifying monomer, it is preferable to use an organic peroxide in combination. The organic peroxide may be any one generally used for a polyolefin grafting reaction, such as benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxyacetate, and t-butylperoxy. Benzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butyl Peroxy) hexyne-3 and the like, which are suitably used alone or in combination of two or more.

In particular, dicumyl peroxide, 2,5-
One of dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 and the like Species or two or more species are more preferably used.

If the amount of the organic peroxide used is too small, the conversion of the grafting reaction is insufficient, and if it is too large, so-called β-cleavage of the polypropylene occurs remarkably, and the molecular weight of the modified product is too low, and the physical properties are too low. In some cases, foaming failure may occur due to a decrease or a decrease in viscosity. In consideration of these points, the amount of the organic peroxide to be used is preferably 0.001 to 0.5 part by weight, preferably 0.005 to 0.15 part by weight, based on 100 parts by weight of the polyolefin resin. More preferably, there is.

In order to obtain a modified resin, a polyolefin resin and a modifying monomer are melt-mixed under predetermined conditions using a kneading apparatus such as a screw extruder or a kneader and reacted. The reaction temperature at this time is 170 ° C. or higher and the decomposition temperature of the polyolefin resin or lower, preferably 200 ° C. to 2 ° C.
50 ° C. If the melt mixing temperature is lower than 170 ° C., the denaturation is insufficient, and the expansion ratio of the finally obtained foam may not be sufficiently high. If it exceeds 250 ° C., the polyolefin resin is easily decomposed.

According to a fifth aspect of the present invention, there is provided a method for producing a foamable composite sheet, comprising reacting a polyolefin-based resin with a modifying monomer, adding a thermally decomposable chemical foaming agent to the resulting modified resin, and obtaining a foamable composite sheet. The resin composition is shaped into a sheet, and a sheet having a strength capable of suppressing an in-plane foaming force generated when the sheet is heated and foamed is laminated on at least one surface of the obtained foamable sheet. How to

The modified resin may be a melt-blended resin of the same or different type of unmodified polyolefin resin. By using a blend of such a modified resin and an unmodified resin, the flowability of the foamable resin composition obtained is improved, and thereby, an extremely thin foamable raw material can be molded, and as a result, a thin sheet It is possible to manufacture a composite foam. In addition, the improvement of the fluidity of the foamable resin composition works favorably to form spindle-shaped cells, and as a result, it is possible to obtain a foam having higher compressive strength.

The unmodified polyolefin resin may be the same as described above in the definition of the polyolefin resin before modification of the modified resin.

The type of the unmodified polyolefin-based resin is determined based on the moldability, appearance, and adhesion to the sheet-like material of the foamable composite sheet obtained, and the expansion ratio, mechanical properties, and thermal properties of the composite foam obtained therefrom. , Cell shape and the like. For example, if it is desired to improve the flowability of the foam, a resin having a low viscosity is used as the unmodified polyolefin resin. If a soft foam is desired, a low density polyolefin is used as the unmodified resin.

The ratio of the modified resin to the unmodified polyolefin resin is preferably 50 to 200 parts by weight, more preferably 70 to 200 parts by weight, based on 100 parts by weight of the modified resin.
130 parts by weight are blended. If the proportion of the unmodified polyolefin-based resin is too large, the melt tension required for foaming cannot be maintained, so that the foaming ratio may be reduced and a good foam may not be obtained.

The pyrolytic chemical blowing agent that can be used in the present invention is not particularly limited as long as it generates a decomposition gas by heating. Representative examples of the thermal decomposition type chemical blowing agent are azodicarbonamide, benzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, toluenesulfonyl hydrazide, and 4,4-oxybis (benzenesulfonyl hydrazide). These may be used alone or in combination of two or more. Among them, azodicarbonamide is particularly preferably used.

The thermal decomposition type chemical foaming agent is used in an appropriate amount in the range of 1 to 50 parts by weight, preferably 2 to 35 parts by weight, based on 100 parts by weight of the modified resin, according to the desired expansion ratio. .

In order to obtain a foamable resin composition by kneading the thermally decomposable chemical foaming agent with the modified resin obtained from the polyolefin resin and the modifying monomer in this manner, the melt kneading apparatus for the reaction described above is used. And a different melt-kneading device for mixing the blowing agent (the structure may be the same as that of the melt-kneading device for the reaction), and the maximum temperature at which the blowing agent is not substantially decomposed It is preferable to mix both.
The mode of the melt kneading is as follows.

(A) In a batch or continuous melt-kneading apparatus for reaction, a polyolefin-based resin is melt-mixed with a modifying monomer and reacted, and the resulting modified resin is taken out of the melt-kneading apparatus and solidified. After performing granulation, etc.
The resin composition is transferred to a batch-type or continuous kneading apparatus for mixing a foaming agent, into which a foaming agent is added, and both are melt-kneaded to obtain a foamable resin composition.

(B) In a batch-type melt-kneading apparatus for reaction, a polyolefin resin is melt-mixed with a modifying monomer and reacted, and the resulting modified resin is substantially decomposed in the kneading apparatus. After cooling to a temperature that does not cause decomposition or a temperature that does not decompose in a large amount, a foaming agent is added thereto, and the two are melt-kneaded to obtain a foamable resin composition.

(C) In a screw extruder for reaction (continuous melt kneading apparatus), the polyolefin resin is melt-mixed with the modifying monomer at a temperature of 170 ° C. or higher to react, and the resulting modified resin is foamed. The temperature is lowered to a temperature at which the agent does not substantially decompose or a large amount does not decompose,
Further, a foaming agent is charged from a supply port provided in the middle of the screw extruder, and the two are melt-kneaded to obtain a foamable resin composition.

(D) In another mode of the continuous operation, two screw extruders are connected, and the polyolefin resin is melt-mixed with the modifying monomer in the first unit and reacted to obtain the modified product. After lowering the temperature of the resin in the same manner as described above, the same resin composition is transferred to a second unit, a foaming agent is added thereto, and the two are melt-kneaded to obtain a foamable resin composition.

The foamable resin composition obtained by kneading the mixture with a thermal decomposition type chemical foaming agent is shaped into a sheet. As a shaping method, in addition to extrusion molding, a method generally performed in plastic molding such as press molding, blow molding, calendaring molding, injection molding, or the like can be applied.

In particular, the foamable resin composition obtained according to the above-mentioned methods (a) and (b) is taken out from a batch-type kneading device for mixing a foaming agent, and is put into a screw extruder to continuously form a sheet. Method of shaping into a shape, or the above (a)
According to the methods (c) and (d), a method of directly shaping the foamable resin composition discharged from the screw extruder is preferable from the viewpoint of productivity.

The material constituting the sheet-like material that can be used in the present invention can be freely selected from metals such as paper, cloth, wood, iron, etc., non-ferrous metals, plastics, glass, and inorganic materials, and is not particularly limited. When the sheet is laminated and integrated with the foamable sheet, it is desirable that the sheet exhibit a certain degree of adhesiveness with the foamable sheet. Any material can be used as long as it can be bonded to the foamable sheet by using an adhesive or an adhesive as appropriate.

The sheet-like material has a strength capable of suppressing in-plane foaming when the foamable sheet is heated and foamed. If the strength of the sheet-like material is too low, the sheet-like material may be torn during foaming, and the foaming of the foamable sheet in the in-plane direction may not be sufficiently suppressed. Therefore, as the sheet-like material for suppressing the in-plane foaming, for example, when the foaming ratio is 10, a sheet having a tensile strength of 100 N / m or more is preferable.

Examples of the sheet material that can be suitably used in the present invention include glass cloth, cold gauze, woven or nonwoven fabric, needle punched nonwoven fabric, and paper. The glass cloth refers to a surface mat obtained by forming glass fibers and a glass roving woven. The cold gauze, the nonwoven fabric, and the needle punch are mainly made of synthetic fibers such as polyester and nylon. The woven fabric may be made of general natural fibers or synthetic fibers. Note that the surface mat may include a binder for binding the short glass fibers to each other.

The binder is not particularly limited as long as the tensile strength of the sheet material satisfies the above range.
For example, thermoplastic resins such as polyvinyl alcohol, saturated polyester and acrylic resin, and thermosetting resins such as epoxy resin and unsaturated polyester can be used.
Examples of the organic fibers constituting the woven or nonwoven fabric include polyester fibers, cotton, acrylic fibers, nylon fibers, carbon fibers, and aramid fibers. By using these sheet materials, it is possible to obtain a polyolefin resin composite foam having a light weight and a high compressive strength.

Further, sheet-like materials usable in the present invention include:
A metal sheet, for example, an iron sheet or a sheet made of a non-ferrous metal such as aluminum, titanium, or copper may be used. The iron sheet includes a molten zinc steel sheet, a molten zinc aluminum alloy steel sheet, a stainless steel sheet, and the like. Such a metal sheet has a thickness of 0.1 mm.
Rolled thin sheets of from 1 mm to 2 mm are particularly preferably used.

In this case, these metals may be arbitrarily plated, may be coated with an organic paint or inorganic paint, or may be coated with an adhesive. When these metal sheets are used, the resulting polyolefin-based resin composite foam can be a lightweight metal composite plate. Compared to a metal plate with a thickness of 1 to 5 mm or a metal composite plate in which a polyethylene layer is arranged as an intermediate layer, it is possible to further reduce the weight and cost without causing extreme shortage of strength in practical use. It has the merit that can be achieved. In addition, since the composite foam is manufactured by foaming a foamable composite sheet, the surface smoothness is extremely excellent as compared with a metal composite plate in which a metal sheet is pasted on the foam.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1A is a horizontal sectional view showing an outline of an extrusion molding apparatus provided with the adapter of the present invention, and FIG. 1B is a plan view showing a sheet extruded from a T-die. The adapter 4 of the present invention is disposed between the barrel 1 of the twin-screw extruder 2 and the T-die fitting 6, and the T-die 3
Thus, the foamable sheet 8 shown in FIG. 1 (b) is extruded.

FIG. 2 is a sectional view taken along the line II-II in FIG. That is, FIG. 2 is a cross-sectional view at a position where the head of the biaxial screw 13 is cut, and the position of the biaxial screw 13 in the adapter 4 and the resin flow formed by the inner surface of the adapter 4 and the biaxial screw 13 The road is revealed. Further, a resin stagnation 5 is generated in a space (closest space) ahead of the head of the twin screw 13, and the resin stagnation 5 is formed on both side flow paths 11, 12 of the twin screw 13.
Located within.

FIG. 3 is a sectional view taken along the line III-III in FIG. According to FIGS. 1 and 3, the resin extruded from the extruder 2 has a central channel 10 at the inlet of the adapter 4.
3 shows that the resin flow rate of the central flow path 10 is divided into three flow paths 11 and 12.
Is set to be larger than the total of the resin flow rates. 4 is a sectional view taken along the line IV-IV in FIG. 1 (a), FIG. 5 is a sectional view taken along the line VV in FIG. 1 (a), and FIG.
FIGS. 4 to 6 are cross-sectional views taken along the line VI-VI. FIGS. 4 to 6 show a pair of flow marks 7, 7 because most of the resin flow rate in the adapter 4 flows to the central flow path 10 of the adapter 4. This indicates that the adapter is located in both side flow paths 11 and 12 which are located closer to the inner surface side of the adapter.

FIGS. 4 to 6 show that the inlet of the adapter 4 is divided into the central channel 10 and the two channels 11, 12, and the two channels 11, 12 join the central channel 10. It also shows how you are. The cross-sectional shape of the resin flow channel in FIG. 6 is not particularly limited, but is preferably an elliptical shape, an elliptical shape, or a circular shape.

FIG. 7 is an enlarged sectional view corresponding to FIG. 3 and schematically showing the position of the inner surface of the adapter of the present invention and the conventional adapter. The position of the inner surface of the conventional adapter is indicated by a broken line. ing. FIG. 8 is a cross-sectional view corresponding to FIG. 6 and illustrating the position of the flow mark.

The flow mark 7 is generated at the tip of the screw head, which is the tip of the twin screw 13, and the flow mark 7 at the end of the adapter moves to both ends in the adapter. In this way, by reducing the distance between the tip of the biaxial screw and the inner wall surface of the adapter and positioning the flow mark 7 on the outermost side of the adapter 4, the foamable sheet 8 obtained through the T-die 3 is then removed. ,
The flow mark 7 can be shifted to both sides of the sheet, and by cutting off the flow mark 7 together with both sides, the effective width of the product can be increased.

Specifically, in FIG. 7, when the distance f between the center of the screw tip and the inner wall of the conventional adapter is narrowed by the distance g, the distance x from the flow mark to the inner wall of the adapter at the end of the adapter is expressed as x / resin flow. The radius y of the road becomes smaller (see FIG. 8). Also, f> g and x / y
Since x is greater than 0, x approaches 0 when g is as close to f as possible, and the flow mark can be brought closer to the end of the resin flow path.

From such a viewpoint, the distance between the inner surface of the adapter and the center of the screw head of the adjacent screw is 0.1 to 0.1 times the distance from the inner surface of the adapter to the opposite inner surface. It needs to be 10%. Preferably, it is 3 to 6%.

Here, the distance from the inner surface of the adapter to the center of the screw head of the adjacent screw and the distance from the inner surface of the adapter to the opposite inner surface are both two in the direction perpendicular to the axial direction of the screw. Means the distance measured on a line passing through the tip of the screw. Thus, for example, in FIG. 7, the distance from the inner surface of the adapter to the center of the screw head of the adjacent screw is represented by fg, and in FIG. 1, the distance from the inner surface of the adapter to the opposing inner surface is R. Is represented.

If the distance from the inner surface of the adapter to the center of the screw head of the adjacent screw is less than 0.1% of the distance from the inner surface of the adapter to the opposing inner surface,
The fluidity of the thermoplastic resin deteriorates, molding failure occurs,
On the other hand, if it exceeds 10%, the flow mark cannot be effectively brought to the end of the molded product, resulting in poor product efficiency.

The thermoplastic resin extrusion molding apparatus according to the second aspect is provided with the adapter, the twin screw extruder, and the die, and the distance fg in the adapter is measured from the inner surface of the adapter. It must be 0.1 to 10% of the distance R between the opposing inner surfaces.

In the method for producing a thermoplastic resin sheet according to the third aspect, the thermoplastic resin is extruded into a sheet by using the extrusion molding apparatus according to the second aspect, and is formed on both sides of the obtained molded article. The flow mark may be cut off along with both sides of the molded product, and the remaining portion may be used as the product.

The method for producing a foamed thermoplastic resin sheet according to claim 4 is a method for producing a foamed resin composition containing a thermoplastic resin and a thermal decomposition type chemical foaming agent. The resulting foamable sheet is foamed, flow marks generated on both sides of the sheet are cut off together with both sides of the sheet, and the remainder is used as a product.

In the method for producing an expandable composite sheet according to claim 5, an expandable resin composition containing a modified resin obtained by reacting a polyolefin resin with a modifying monomer and a pyrolytic chemical blowing agent. The product is shaped into a sheet using the extrusion molding apparatus according to claim 2, and foaming in the in-plane direction when heating and foaming the sheet can be suppressed on at least one surface of the obtained foamable sheet. It is preferable to laminate a sheet having strength.

The above-mentioned modifying monomer may be introduced into the extruder from the hopper simultaneously with the polyolefin resin. Particularly, some of divinylbenzene and allyl-based polyfunctional monomers are liquid at room temperature and pressure. It is preferable that the polyolefin resin is supplied from the extruder through a liquid injection hole provided at a downstream portion of the molten resin, rather than at a position where the polyolefin resin is melted, because the liquid can be uniformly dispersed in the molten resin. At this time, it is desirable that the liquid monomer be sent by a pressure-feeding pump such as a plunger pump.

When an organic peroxide is used in combination with the modifying monomer, the organic peroxide is preliminarily mixed with the modifying monomer and then added simultaneously, or the organic peroxide is separated before and after the monomer is added. The method of charging can be applied.

The modified resin may be melt-blended with an unmodified polyolefin resin of the same or different type (hereinafter collectively referred to as a resin for blending) for the purpose of improving the fluidity. By using a blend of such a modified resin and a blending resin, the flowability of the foamable resin composition to be obtained is improved, whereby an extremely thin raw foam can be molded, and as a result, a thin composite foam Production of sheets becomes possible.

In addition, the fluidity works favorably for forming spindle-shaped cells, and as a result, it is possible to obtain a foam having higher compressive strength. The unmodified polyolefin resin may be the one described above in the definition of the polyolefin resin before the modification of the modified resin.

The type and amount of the resin for blending are determined according to the moldability, appearance, and adhesion to the sheet-like material of the foamable composite sheet obtained, and the expansion ratio, mechanical properties, thermal properties and thermal expansion of the composite foam obtained therefrom. It is appropriately adjusted depending on physical properties, cell shape and the like. In particular, it is preferable to newly melt-blend 50 to 200 parts by weight of the same or different unmodified polyolefin-based resin with respect to 100 parts by weight of the modified polyolefin-based resin. More preferably, 70 to 130 parts by weight are blended. If the proportion of the resin for blending is too large, the melt tension required for foaming cannot be maintained, so that the foaming ratio is reduced and a good foam cannot be obtained.

The method of laminating the sheet-like material on at least one side of the foamable sheet is not particularly limited. For example, (a) a method of attaching the sheet-like material to a foamed sheet that has been cooled and solidified while heating the sheet-like material. And (b) a method in which a foamable sheet is heated until it is in a molten state, and this is thermally fused to a sheet-like material.

The method (a) is most preferable for ensuring the thickness accuracy of the foamable composite sheet. In the heat fusion of the method (b), for example, a sheet-like material is lightly laminated on both sides of a molten foamable sheet immediately after being extruded from a T-die, and these are passed between opposed cooling rolls. Then, a method in which the two are integrated by the pressing force of the roll is preferable. In addition, as described above, laminating and integrating a foamable sheet and a sheet-like material means that, when the foamable sheet and the sheet-like material are to be peeled off at an interface between them, a high rate of material destruction occurs. Means that both are fixed.

The method for producing a composite foamed sheet according to the sixth aspect is to heat and expand the foamable composite sheet obtained by the method according to the fifth aspect. The foamable composite sheet obtained as described above can be foamed to a desired expansion ratio under normal pressure or constant pressure by heating under appropriate temperature conditions.

The heating is usually carried out in a temperature range from the decomposition temperature of the thermal decomposition type chemical foaming agent to the decomposition temperature + 100 ° C. In particular, as a continuous foaming apparatus, in addition to a take-up foamer that foams while taking out a foam at an outlet side of a heating furnace, a belt-type foamer, a vertical or horizontal foaming furnace, a hot air thermostat, or an oil bath, metal A hot bath such as a bath or a salt bath is used.

(Operation) The inner wall of the adapter is made narrower toward the screw than before, that is, the distance from the inner surface of the adapter to the center of the screw head of the adjacent screw is set to the distance from the inner surface of the adapter to the opposite inner surface. By using 0.1 to 10% of the interval, the cross-sectional area of the resin flow path is increased at the center, and the flow mark estimated to be formed by the stagnation of the resin in the screw head is used with the adapter of the present invention. This makes it possible to approach the end of the die, and in the case of a molded product, for example, a thermoplastic resin sheet, the position of the flow mark is formed at a position corresponding to the end of the die. Therefore, when the adapter of the present invention is used, when extrusion molding is performed with a die, the flow mark is close to the end of the molded product, so that the effective product area can be increased.

The present invention will be described more specifically with reference to examples. (Example 1) (1) Preparation of modified polyolefin-based resin A BT40 (plastic engineering laboratory) co-rotating twin-screw extruder was used as a modifying screw extruder. This extruder was equipped with a self-wiping double-start screw, its L / D was 35 and D was 39 mm. The cylinder barrel consisted of first to fourth barrels from upstream to downstream of the extruder. The die was a three-hole strand die, and a vacuum vent was installed in the fourth barrel to collect volatiles.

The operating conditions were as follows.

First, a polyolefin resin and a dioxime compound are separately charged from the rear end hopper into the modifying screw extruder having the above-mentioned structure, and the two are melt-mixed.
A modified resin was obtained. At this time, the volatile components generated in the extruder were evacuated by a vacuum vent. Polyolefin resin is a polypropylene random copolymer (Mitsubishi Chemical "E"
G8 ", MI: 0.8, density: 900 kg / m ³ ), and the supply amount was 10 kg / h.

The modifying monomer (dioxime compound) is p
-Quinone dioxime ("Barnock G" manufactured by Ouchi Shinko Chemical Co., Ltd.)
MP ”), and the supply amount was 0.75 parts by weight based on 100 parts by weight of the polyolefin resin. The modified resin obtained by melt-mixing the polyolefin resin and the dioxime compound was discharged from a strand die, cooled with water, and cut with a pelletizer to obtain pellets of the modified resin.

(2) Preparation of Foamable Resin Composition and Preparation of Composite Sheet As a screw extruder for kneading a foaming agent, a TEX-44 type (manufactured by Nippon Steel Works Co., Ltd.) co-rotating twin screw extruder was used. The extruder was equipped with a self-wiping double screw, the L / D was 45.5 and the D was 47 mm. Cylinder barrels from upstream to downstream of extruder
Made of barrel, forming die 500mm wide and 3.5 thick
mm T-die. The temperature setting categories are as follows.

The first barrel is constantly cooled. The first zone; the second to fourth barrels. Second zone; 5th to 8th barrels. Third zone: 9th to 12th barrels. Fourth zone: die and adapter part. A side feeder is installed in the sixth barrel to supply the blowing agent, and a vacuum vent is installed in the eleventh barrel to collect volatiles.

The operating conditions were as follows. The modified resin obtained as described above was supplied from a modifying screw extruder to a blowing agent kneading screw extruder.
The supply amount of the modified resin was 20 kg / h. A foaming agent was supplied to the extruder from the side feeder and dispersed. The blowing agent was azodicarbonamide (ADCA), and the supply amount was 1 kg / h.

The foamable resin composition obtained by kneading the modified resin and the foaming agent was passed through the adapter of the present invention (the length f in FIG. 4 was usually 6 mm.
By setting the length g to 3 mm, the distance from the screw tip to the inner wall of the adapter was set to 3 mm), 500 mm
When extruding from a T die with a width and passing through three cooling rolls,
A nonwoven fabric made of polyethylene terephthalate (manufactured by Toyobo Co., Ltd., “Spanbond Equle 6301A”, weighing 30 g / m 2) on both the front and back surfaces of the foamable resin composition sheet
2. Tensile strength: 1570 N / m length, 1180 N / width
m) was heat-fused to obtain a polyolefin resin foamable composite sheet having a width of 460 mm and a thickness of 3.4 mm. The distance R from the inner surface of the adapter to the opposite inner surface in FIG.
Was 55 mm.

(3) Foaming The resulting polyolefin resin foamable composite sheet was foamed by heating at 230 ° C. for about 8 minutes using a continuous foaming machine having a heating zone to obtain a composite foam. (4) Performance Evaluation Performance of the obtained composite foam was evaluated for the following items. Measurement of the effective width in the adapter: The distance x in FIG. 8 was measured. The radius y of the inner diameter of the adapter end is 15 mm
And・ Measurement of effective width as a product: In a composite foam, the effective width of a product when a flow mark portion is cut off is measured.

Measurement of expansion ratio: In a composite foam, the expansion ratio is measured. -Compressive strength measurement: The compressive strength of a composite foam is measured.

Example 2 In the preparation of the foamable resin composition and the preparation of the composite sheet (2), the interval of the length g in FIG.
mm, a polyolefin-based resin foamable composite sheet was obtained in exactly the same manner as in Example 1, except that the distance from the screw tip to the inner wall of the adapter was 5 mm. The foam was heated and foamed to obtain a composite foam, and the performance was evaluated by the same method.

(Comparative Example 1) In the preparation of the foamable resin composition and the preparation of the composite sheet (2), the conventional adapter shown by the broken line in FIG. (The distance to 6 mm) was obtained in the same manner as in Example 1 to obtain a polyolefin-based resin foamable composite sheet, which was heated and foamed in the same manner to obtain a composite foam. Then, the performance was evaluated in the same manner. Table 1 summarizes the evaluation results of Examples 1 and 2 and Comparative Example 1.

[0089]

[Table 1]

From Table 1, it was confirmed that the composite foams obtained in the examples exhibited good performance in any of the items.

[0091]

The adapter of the present invention is constituted as described above, and the thermoplastic resin extrusion molding apparatus of the present invention comprises the adapter of the present invention, a twin screw extruder and a die. In addition, according to the extrusion molding apparatus provided with the adapter of the present invention or the thermoplastic resin extrusion molding apparatus of the present invention, the flow marks are shifted to both ends of the thermoplastic resin molded product. Therefore, according to the third aspect of the invention,
By cutting off both sides of the sheet including the flow mark, it is possible to increase the effective width of the molded product. According to the fourth aspect of the present invention, after the obtained thermoplastic foamable sheet is foamed, the effective width of the foamable sheet product can be expanded by cutting off both sides of the sheet including the flow mark. it can. According to the invention as set forth in claim 5, a polyolefin-based sheet in which a sheet-like material having a strength capable of suppressing in-plane foaming when the sheet is heated and foamed is laminated on at least one surface of the foamable sheet. By foaming the resin foamable composite sheet,
A composite foam in which the cells of the foam have a spindle shape and whose major axis is oriented in the thickness direction is obtained. For this reason, it is possible to produce a composite foam having significantly higher compressive strength than conventional foams and excellent performance. According to the invention of claim 6, by heating and foaming the expandable composite sheet obtained by the method of claim 5, it is possible to easily provide a composite foam having the above excellent performance. When a sheet-like material such as cloth, nonwoven fabric, and cold gauze is used, the obtained composite foam is flexible in the bending direction despite its high compressive strength. Also,
When using a ferrous or non-ferrous metal sheet, the resulting composite foam has a surface smoothness equivalent to that of a conventional metal composite plate, without causing a practical lack of strength. , A significant reduction in weight can be achieved.

[Brief description of the drawings]

FIG. 1 (a) is a horizontal sectional view showing an outline of an extrusion molding apparatus provided with an adapter used in Example 1. FIG.
(b) is a plan view showing a sheet extruded from a T-die.

FIG. 2 is a sectional view taken along the line II-II in FIG. 1 (a).

FIG. 3 is a sectional view taken along line III-III in FIG. 1 (a).

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1 (a).

FIG. 5 is a cross-sectional view taken along line VV in FIG. 1 (a).

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 1 (a).

FIG. 7 is an enlarged cross-sectional view corresponding to FIG. 3, schematically showing the positions of the inner surfaces of the adapter of the present invention and a conventional adapter.

FIG. 8 is an enlarged cross-sectional view corresponding to FIG. 6 and illustrating the position of a flow mark.

FIG. 9 (a) is a horizontal sectional view showing a conventional technique and corresponding to FIG. 1 (a). FIG. 9 (b) is a plan view corresponding to FIG. 1 (b), showing the foamable sheet extruded from the T-die.

[Explanation of symbols]

1: Barrel 2: Twin screw extruder 3: T die 4, 14: Adapter 5: Resin resin 6: T die mounting bracket 7: Flow mark 8: Foamable sheet 10: Central flow channel 11, 12: Both flow channels 13: biaxial screw R: distance from the inner surface of the adapter to the opposing inner surface fg: distance from the inner surface of the adapter to the center of the screw head of the adjacent screw

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 7:00 B29C 67/22 F term (Reference) 4F207 AA03 AA11H AB02 AC01 AD05 AD08 AD16 AG01 AG03 AG20 AM36 KA01 KA11 KF04 KK13 KK30 KK81 KL15 KL28 KL30 KL31 KL42 KL55 KL84 4F212 AA03 AA03J AB02 AD03 AD04 AD05 AD06 AD08 AD16 AG03 AG20 AM32 UA09 UB02 UF01 UG02 UG05 UG07 UH18 UN11 4J002 BB031 BB01 BB01 BB01 BB01 BB01 BB05 (54) [Title of the Invention] An adapter in an extrusion molding apparatus, an extrusion molding apparatus, a method for producing a thermoplastic resin sheet, a method for producing a thermoplastic resin foam sheet, a method for producing a foamable composite sheet, and composite foaming Sheet manufacturing method

Claims (6)

[Claims] 1. An adapter in a thermoplastic resin extrusion molding apparatus comprising a twin screw extruder, an adapter and a die, wherein the distance from the inner surface of the adapter to the center of the screw head of an adjacent screw is equal to that of the adapter. 0.1-1 of the distance from the inner surface to the opposing inner surface
0%, so that the position of the flow mark of the molded product caused by the stagnation of the thermoplastic resin in the space before the head of the screw is formed at a position corresponding to the end of the die. An adapter in an extrusion molding device. 2. In a thermoplastic resin extrusion molding apparatus provided with a twin screw extruder, an adapter and a die, a distance from an inner surface of an adapter to a center portion of a screw head of an adjacent screw is set at an opposite inner surface of the adapter. The gap between them is 0.1 to 10%, and the position of the flow mark of the molded product caused by the stagnation of the thermoplastic resin at the tip of the screw head is formed at a position corresponding to both sides of the die. An apparatus for extruding a thermoplastic resin, characterized in that the apparatus is extruded. 3. A thermoplastic resin is extruded into a sheet using the extrusion molding apparatus according to claim 2, and flow marks formed on both sides of the obtained molded product are cut off together with both sides of the molded product, and the remaining portion is removed. A method for producing a thermoplastic resin sheet, comprising: 4. A foamable resin composition comprising a foamable resin composition containing a thermoplastic resin and a thermally decomposable chemical foaming agent, wherein the foamable resin composition is formed into a sheet using the extrusion molding apparatus according to claim 2. Is heated and foamed, the flow marks generated on both sides of the sheet are cut off together with both sides of the sheet, and the remaining part is made into a product. 5. An extrudable resin composition containing a modified resin obtained by reacting a polyolefin resin with a modifying monomer and a pyrolytic chemical foaming agent by using the extrusion molding apparatus according to claim 2. It is shaped into a sheet, and at least one surface of the obtained foamable sheet is laminated with a sheet having a strength capable of suppressing foaming in an in-plane direction when the sheet is heated and foamed. , A method for producing an expandable composite sheet. 6. The foamable composite sheet obtained by the method according to claim 5, which is heated and foamed,
A method for producing a composite foam sheet.