JPS6050130B2 - Manufacturing method of laminated sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a laminated sheet in which a polyolefin resin film is laminated on one side of a polystyrene resin foam sheet via an adhesive resin layer.

Polystyrene resin foam sheet has moderate rigidity,
Although it has good shape retention, it is inferior to polyolefin resins in terms of oil resistance, solvent resistance, gas permeability, etc.

Although polyolefin resins do not have the above-mentioned drawbacks of polystyrene resins, polystyrene resins and polyolefin resins have poor compatibility and are difficult to fuse together even when heated. Even if an adhesive is used when attaching sheets that do not have heat fusion properties to each other, such as a polystyrene foam sheet and a polyolefin resin film, sufficient heat or pressure is required to prevent air bubbles in the foam sheet from forming. It has the disadvantage of being destroyed or crushed by heat, resulting in a decrease in quality. Also, adhesives using solvents dissolve polystyrene and cannot be used. Conventionally, as a method for producing a laminated sheet consisting of a foamed layer and a non-foamed layer, a thermoplastic resin mixed with a foaming agent is heated and melted for extrusion molding as described in Japanese Patent Publication No. 48-3775. A non-foaming thermoplastic resin is fed into a resin passage having an annular cross-section of a mold, heated and melted, and concentrically merged inside the resin passage to form an integrated tubular body for extrusion molding. There is a method for producing a thermoplastic resin tube consisting of a foamed outer layer and an unfoamed inner layer by extruding the resin through an annular extrusion port of a mold and foaming the outer layer outside the annular extrusion port. When applying the conventional method to foamable polystyrene resin and polyolefin resin, the inner and outer layers of resins that do not have heat-fusibility to each other, such as a polystyrene foam sheet and a polyolefin resin, will adhere to each other. Without this, the lamination is merely an appearance and is easily peeled off, so it is of no practical use.

Moreover, even when such a method is used, even when an adhesive resin that has adhesive properties to both the foamable polystyrene resin and the polyolefin resin is interposed between the two resin layers and laminated, the polyolefin resin layer cannot be formed by extrusion molding. Adiabatic expansion due to foaming after leaving the mold. It enters the inside of the cylindrical foam layer of polystyrene resin, which naturally cools when stretched, maintaining the temperature inside the balloon at a high level, and coarsening the air bubbles at the interface with the foam layer of polystyrene resin. This results in weaker fusion and poorer appearance. In addition, the polystyrene resin layer, which is a foamed layer that comes out of the mold for molding, has a larger expansion force in the direction of increasing the balloon diameter than the polyolefin resin layer, which is a non-foamed layer. It will be pulled by the polystyrene resin layer, which is a foam layer, and the fusion will be significantly weakened. Furthermore, foamable resins require sophisticated temperature control in order to obtain a uniform foam. Therefore, when considering the difficulty of temperature control near the annular extrusion port of an extrusion mold, it is more difficult to control the temperature in the outer annular body part than in the cylindrical body part inside the annular extrusion mouth.
The conventional method has the drawback of using a difficult method. As a result of intensive research into solving the drawbacks of the conventional manufacturing methods described above, the present inventors were able to produce a laminated foam sheet in which a polyolefin resin film was adhered to one side of a polystyrene resin foam sheet via an adhesive layer. The adhesive strength between the resin foam sheet and polyolefin resin film is high and uniform. It has the appropriate rigidity of a polystyrene resin foam sheet, good shape retention, and has excellent oil resistance and solvent resistance of a polyolefin resin film on one side, as well as extremely low gas permeability. We have developed a method for manufacturing laminated foam sheets that can continuously produce large quantities of laminated foam sheets, which are extremely useful as materials for manufacturing various containers and other processed products.

In the present invention, three types of resins, a polystyrene resin containing a foaming agent, a polyolefin resin, and an adhesive resin capable of adhering to both of the above resins, are heated and melted using an extrusion device, and then molded into an annular shape of a mold. Laminated from the extrusion port and simultaneously extruded, a polyolefin resin film was adhered to one side of the polystyrene resin foam sheet via an adhesive resin layer 3
In the method of manufacturing a laminated sheet consisting of layers, when the three types of molten resins are combined into one body by thermal fusion between the extrusion port of the extrusion device and the annular extrusion port of the molding die, In the annular extrusion port, a polyolefin resin layer is provided on the outside,
The annular body is made up of an adhesive resin layer in the middle and a polystyrene resin layer containing a foaming agent on the inside.The annular body is extruded from an annular extrusion port under atmospheric pressure, and the foaming agent The gist of the present invention is a method for producing a laminated sheet, which comprises foaming a polystyrene resin containing a polystyrene resin to produce a three-layer laminate having a foamed resin layer.

The polystyrene resin used in the method of the present invention is a polymer mainly composed of styrene, including styrene homopolymer, butadiene, acrylonitrile, α-methylstyrene, and other monomers that can be copolymerized with styrene. It is a copolymer of these, and can be used alone or in a mixture of two or more thereof.

The polyolefin resin is a polymer mainly composed of ethylene, and is a homopolymer or a copolymer with vinyl acetate, methyl methacrylate, acrylate, or propylene or other monomers that can be copolymerized with ethylene; Alternatively, a polymer mainly composed of propylene is used, and a resin that is a homopolymer of this homopolymer or a copolymer with vinyl acetate, methyl methacrylate, acrylate, or ethylene or other monomers that can be copolymerized with propylene is used. It will be done.

In the method of the present invention, the adhesive resin may include thermoplastic rubbers such as ethylene-vinyl acetate copolymer or polybutadiene, polyisoprene, styrene-butadiene copolymer or styrene-isoprene copolymer; In use, in order to adjust the adhesive strength, a mixture of two or more of these resins or a mixture of polyethylene may be used.

In addition, the blowing agents used in the present invention include volatile organic substances such as propane, butane, pentane, paraffinic hydrocarbons such as hexane, dichlorodifluoromethane, dichlorotetrafluoroethane, monochlorodifluoromethane, trichloromonochloromethane, etc. Compressed or liquefied gases of chlorinated fluorocarbons such as fluoromethane, trichlorotrifluoroethane, dichloromonofluoromethane, octafluorocyclobutane.

Alternatively, chemical blowing agents such as azodicarbonamide, azobisisobutyldinitrile, azodicarbamic acid amide, and benzenesulfonyl hydrazide, which are organic compounds generated by heating an inorganic gas such as carbon dioxide or nitrogen, are used. These blowing agents may be used alone or in combination, and may be used in an amount of 0.5 to 0.5% by weight based on the polystyrene resin.
It is blended at a ratio of 20%.

For polystyrene resin, bubble control agents include inorganic substances such as talc, silica, kaolin, clay, calcium carbonate, and aluminum sulfate, fatty acid metal salts such as barium stearate and calcium stearate, and mixtures of sodium bicarbonate and citric acid. may be blended in a proportion of 0.05 to 5% by weight based on the polystyrene resin.

In the present invention, the method for obtaining a heated melt of polystyrene resin containing a blowing agent is to feed the polystyrene resin into which the blowing agent has been mixed in advance into a cylinder of an extrusion device, and knead it with a cell regulator. In the process of heating and melting polystyrene-based resin while kneading it with a foam control agent, the polystyrene-based resin is fed into the cylinder of an extrusion device, and a foaming agent is injected into the cylinder during the process of heating and melting while kneading with a foaming agent. A heat-melting method suitable for the resin is used.

Furthermore, in order to heat and melt the polyolefin resin and the adhesive resin, two sets of extrusion devices are used in addition to the extrusion device that heats and melts the polystyrene resin containing the foaming agent.

The polyolefin resin or adhesive resin may be individually fed into a cylinder of a separate extrusion device and heated and melted while being kneaded, or heated and melted using other suitable heating means. The three types of molten resins, foamable polystyrene resin, adhesive resin, and polystyrene resin thus obtained, are transported between the respective extrusion devices and the annular extrusion port of the mold, with a polyolefin resin on the outside and a polystyrene resin in the middle. The resin is laminated inside the resin channel of a molding die so that adhesive resin is placed on the inside and expandable polystyrene resin is placed on the inside.

The order in which three types of molten resins, foamable polystyrene resin, adhesive resin, and polyolefin resin, are laminated is that heated and melted foamable polystyrene resin is supplied from an extrusion device to a cylindrical resin passage, and then In the middle of this resin passage, a supply gate is provided so that the adhesive resin heated and melted by another extrusion device is coated in a ring shape on the outside of the cylindrical body of the expandable polystyrene resin. The polyolefin resin is supplied so as to be coated in a circular manner.

The thus obtained cylindrical molten resin having a triple structure with a polyolefin resin outer shell made of expandable polystyrene resin, adhesive resin, and polyolefin resin is introduced into the annular resin channel of the mold and extruded from the annular extrusion port. Alternatively, heat-melted expandable polystyrene resin is placed in an annular resin passage of a mold, and the outside of the annular body of the expandable polystyrene-based resin is coated with heated-melted adhesive resin in a circular shape. Thereafter, a method is adopted in which a heated and melted polyolefin resin is supplied so as to coat the outside of the adhesive resin in an annular manner and extruded from an annular extrusion port, or a method in which other lamination methods are appropriately combined. . Thus, at the annular extrusion port of the molding die, a three-layer annular structure is formed in which the outside is a polyolefin resin, the middle is an adhesive resin, and the inside is an expandable polystyrene resin. The molten resin is extruded into the atmosphere from the annular extrusion port of the mold, and the inner foamable polystyrene resin is foamed, the outer layer is a polyolefin resin film, the middle is an adhesive resin, and the inner layer is a polystyrene resin foam sheet. A three-layer laminated cylindrical body is made, and this is expanded to a certain diameter and taken by a take-off machine, and if necessary, a part of it is cut open to form a long laminated sheet.

According to the manufacturing method of the present invention, since the expandable polystyrene resin is placed inside the annular extrusion port of the mold, uniform temperature control is easily achieved, and foaming is stable, resulting in uniform foaming. A sheet is obtained.

In addition, when it is extruded into the atmosphere from the annular extrusion port and foamed, it is automatically cooled by adiabatic expansion, so there is no need for difficult means to cool the inner surface of the cylinder. It does not reduce the adhesion of the product or make the bubbles coarser, resulting in poor appearance. In addition, the non-foamed resin layer placed on the outside of the cylinder presses the expandable polystyrene resin and suppresses rapid foaming, thereby maintaining a balance between the radial expansion and foaming of the cylinder, resulting in undulation. This results in a flat sheet. Moreover, the tendency of the expandable polystyrene resin placed inside the cylinder to expand in the radial direction of the cylinder forces the non-foamed resin on the outside to expand, and compressive force acts between them to strengthen the fusion bond. Make it into something! It turns out. The laminated sheet obtained by the production method of the present invention is a laminated sheet in which a polyolefin resin film is strongly fused to one side of a polystyrene resin foam sheet via an adhesive resin, which was previously considered difficult. , the polystyrene resin foam sheet and the polyolefin resin film are strongly adhesively laminated, and the polystyrene resin foam sheet has the rigidity, heat insulation properties, and secondary processability such as vacuum forming, and the polystyrene resin foam sheet has the same properties as the polyolefin resin film. This laminated sheet has excellent properties of smoothness, oil resistance, and solvent resistance, and is extremely useful as a material for manufacturing food containers and other processed products.

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 Using the extrusion apparatus shown in Fig. 1, a polystyrene resin mixed with 1% by weight of talc (average degree of polymerization p = 130
0) into the extruder, and while heating and kneading with the heating cylinder 1 and screw 4, 3% by weight of butane as a blowing agent was injected into the resin, and the mixture was moved in the direction of the cylindrical resin passage 7, and the mixture was heated at 30k9/hour. A molten resin layer of polystyrene resin (hereinafter abbreviated as layer A) was supplied to the cylindrical resin passage 7 at a rate of about 190°C.

On the other hand, styrene and butadiene copolymer (thermoplastic rubber)
is heated and kneaded by a heating cylinder 2 and a screw 5, and supplied to a resin passage 7 via resin passages 8 and 10 at a rate of 2 kg/hour at approximately 180'C (hereinafter referred to as layer B), and supplied by a screw 4. The resin is supplied in an annular manner to the outside of the cylindrical molten resin A layer. On the other hand, high-density polyethylene resin (density 0.96 JISK6760) is heated and kneaded using a heating cylinder 3 and a screw 6, and is supplied to a resin passage 7 via resin passages 9 and 11 at a rate of 6k9 per hour at approximately 200°C (hereinafter referred to as C). layer) molten resin layer A and layer B
It is supplied in an annular manner to the outside of the cylindrical molten resin consisting of layers.

The resin passage 7 has a triple structure in which the center is a cylindrical molten resin layer A, the outer side is surrounded by an annular molten resin layer B, and the outside is surrounded by an annular molten resin layer C. The cylindrical molten resin body is extruded into the atmosphere from the annular extrusion port 13 through the annular resin passage of the molding die 12, and while the molten resin layer A is foamed, it is withdrawn by a conventional method and the pipe diameter is increased; 1 of the bubbles 14 to form the bubbles 14;
The sections were cut and rolled up into a sheet. The obtained laminated sheet has a thickness of 2Tfr1! as shown in FIG. On the surface of the expanded polystyrene sheet 51 with a t1 density of 0.1, a layer with a thickness of 1
The laminated sheet had a uniform three-layer structure and had a good appearance, with a high-density polyethylene film layer 52 having a thickness of 40 μm firmly fused through an adhesive layer 53 made of a 5 μm styrene-butadiene copolymer.

Comparative Example 1 For comparison, using the apparatus and raw materials shown in FIG. 1 in the same manner as in Example 1, a melt of high-density polyethylene resin heated and kneaded by a heating cylinder 1 and a screw 4 was heated at a rate of 6k9/hour. The resin was supplied to the resin passage 7 at about 200'C (hereinafter abbreviated as A'' layer).

On the other hand, the styrene-butadiene copolymer heated and kneaded by the heating cylinder 2 and the screw 5 is supplied to the resin passage 7 at a rate of 2 kg/hour at about 180°C (hereinafter abbreviated as B layer). Columnar molten resin A
On the other hand, polystyrene resin is heated and kneaded using a heating cylinder 3 and a screw 6, while 3% by weight of a blowing agent is injected into the resin, and the blowing agent is injected at 30% per hour.
The resin is supplied to the resin passage 7 at a rate of approximately 190' kg (hereinafter abbreviated as C'' layer) to the outside of the cylindrical molten resin consisting of the molten resin A'' layer and the B layer in an annular manner.

In the resin passage 7, there is a cylindrical molten resin A'' layer at the center,
The annular extrusion port 13 of the molding die 12 carries out a molten resin body having a triple structure in which the outside is surrounded by a molten resin B layer in an annular shape, and the molten resin C'' layer is annularly surrounded on the outside.
The molten resin C'' layer was extruded into a cylindrical body and rolled up into a sheet in the same manner as in Example 1 while foaming.

The obtained laminated sheet was a sheet in which the A'', B, and C'' layers were partially mixed, and had a poor appearance. Example 2 6th
Using the equipment shown in the figure, expandable polystyrene resin (F
= 1450 (containing 4% blowing agent) was heated and kneaded by the extrusion device 21 and fed to the cylindrical resin passage 25 at a rate of 90k9/hour at about 190°C (hereinafter abbreviated as layer D). On the other hand, the polystyrene-polyisoprene copolymer is extruded by an extrusion device 22.
The cylindrical molten resin D layer supplied from the extrusion device 21 is heated and kneaded by the extruder 21 and supplied to the resin passage 26 at a rate of 9 kg/hour at approximately 185°C (hereinafter referred to as E layer). The annular melt is formed into an annular shape on the outside, has a D layer on the inside in the annular resin passage 28 of the molding die 24, and is surrounded by an E layer on the outside. 0.92 JISK6760) is heated and kneaded by the extrusion device 23 at a rate of 18 k9/hour.
Supplied into the resin passage 29 at 5°C (hereinafter abbreviated as F layer)
, a low density polyethylene resin layer is formed on the outside of the annular molten body consisting of the D layer and E layer, and the molten resin D
While foaming the layer, it was rolled up into a sheet shape in the same manner as in Example 1 above. The obtained sheet has a uniform three-layer structure in which a low-density polyethylene layer with a thickness of 18p is firmly fused to the surface of a foamed polystyrene sheet with a thickness of 1WL and a density of 0.09 via a styrene-isoprene copolymer with a thickness of 9μ. It was a laminated sheet with a smooth appearance.

``Brief explanation of the drawings The drawings illustrate the method of manufacturing a laminated sheet of the present invention, and FIG. 1 is a schematic explanatory view of the manufacturing apparatus, and FIG.
-N cross-sectional view, Figure 3 is a cross-sectional view along the line B-B'' in Figure 1, Figure 4
The figure is a sectional view taken along the line C-C'' in FIG. 1.

FIG. 5 is a partially enlarged sectional view of the obtained laminated sheet.
FIG. 6 is a schematic illustration of another manufacturing apparatus. The main symbols in the drawings are as follows. 1, 2, 3... Heating cylinder, 4, 5, 6... No... Screw, 7
, 8, 9, 10, 11... resin passage, 12...
... Molding mold, 13 ... Annular extrusion port, 14
... Valve, 21, 22, 23 ... Extrusion device, 24 ... Molding mold, 25, 26, 27,
28, 29... Resin passageway, 30... Annular extrusion port, 51... Foamed polystyrene sheet,
52...Polyethylene film, 53...
・Adhesive layer.

Claims (1)

[Scope of Claims] 1 Three types of resins, a polystyrene resin containing a foaming agent, a polyolefin resin, and an adhesive resin that has adhesive ability for both of the resins, are heated and melted using an extrusion device, and molded. In a method for manufacturing a laminate sheet consisting of three layers in which a polyolefin resin film is adhered to one side of a polystyrene resin foam sheet via an adhesive resin layer by laminating and simultaneously extruding from an annular extrusion port of a mold, an extrusion device When the three types of molten resins are combined into one body by heat fusion between the extrusion port and the annular extrusion port of the mold, the annular extrusion port has a polyolefin resin layer on the outside, The annular body is made up of an adhesive resin layer in the middle and a polystyrene resin layer containing a foaming agent on the inside.The annular body is extruded from an annular extrusion port under atmospheric pressure, and the foaming agent 1. A method for producing a laminated sheet, which comprises foaming a polystyrene resin containing a polystyrene resin to produce a three-layer laminate having a foamed resin layer. 2 Polystyrene resin is a polymer mainly composed of styrene, and is a styrene homopolymer or a copolymer with butadiene, acrylonitrile, α-methylstyrene, or other monomers that can be copolymerized with styrene, or a mixture of these resins. A method for producing a laminated sheet according to claim 1. 3 The polyolefin resin is a polymer mainly composed of ethylene, and is an ethylene homopolymer or a copolymer resin with vinyl acetate, methyl methacrylate, acrylate, propylene or other monomers that can be copolymerized with ethylene, or propylene. Claim 1, which is a polymer mainly composed of , and is a homopolymer thereof or a copolymer resin with vinyl acetate, methyl methacrylate, acrylate, or ethylene or other monomers copolymerizable with propylene. A method for producing the described laminated sheet. 4. The adhesive resin is a thermoplastic rubber such as ethylene-vinyl acetate copolymer, polybutadiene, polyisoprene, styrene-butadiene copolymer or styrene-isoprene copolymer, or a mixture of these resins or a mixture with polyethylene. A method for manufacturing a laminated sheet according to claim 1.