JPH0780874A - Manufacture of thermoplastic resin foamed sheet having skinned tongued and grooved surface - Google Patents

Abstract

PURPOSE:To obtain thermoplastic resin foamed sheet having tongued and grooved surface, the height of tongue and the depth of groove of which have no limitation, in the forming process of which no deformation of foaming sheet develops and to the tongued and grooved surface of which skin is laminated for reinforcing strength. CONSTITUTION:Foamed sheets 1a and 1b, on the surface of each of which has unskinned tongued and grooved surface produced by profile slicing work, are formed. After that, the foamed sheets 1a and 1b are continuously fed in a heating box 2 so as to melt the tongued and grooved surface by radiating heat energy over the tongued and grooved surface from heat source 4 and then cool the tongued and grooved surface with cooling rolls 5a and 5b. Thus, skin is formed on the tongued and grooved surface having arbitrary size and shape, resulting in obtaining the sheet, the strength of the surface of which is reinforced, and enlarging the range of use application.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is widely used as a material for various industrial products such as cushioning materials, building materials, heat insulating materials, and sound deadening materials, or as various household products such as sundries, sports and leisure products, and sports products. The present invention relates to a method for producing a thermoplastic resin foam sheet having an uneven surface with a skin.

[0002]

2. Description of the Related Art Conventionally, an uneven surface with a skin is provided on the surface of a thermoplastic resin foam sheet having a uniform thickness and relatively flexibility such as polyolefin to increase the cushioning property and heat insulating property of the foam. In addition to the above, it is found in the market that the uneven surface is reinforced.

There are mainly three methods for producing the foamed sheet having this uneven surface. In the first method, a long foamed sheet is manufactured by extrusion molding and once wound,
As shown in FIG.
1 is continuously transferred, one surface thereof is heated by the heater c1, and then the embossing roll d1 is cooled together.
And a mirror-finished backup roll d2 are introduced into the shaping roller d so that the heating surface is on the side of the embossing roll d1, and the foamed sheet e1 having irregularities is manufactured.

The second method is, as shown in FIGS. 3 (a) and 3 (b), a prefabricated long and slightly thick foam sheet b2 is conveyed by a conveyer a2 to FIG. 3 (a). In the direction perpendicular to the paper surface, and in the direction of the arrow in FIG. 3B, in the process, the metal wire feeding pulley f rotates the endless metal wire g, and in the process, the metal is moved by the heater c2. Heat line g. Then, by the vertical reciprocating mechanism (not shown), the foamed sheet b2 is intermittently moved up and down together with the transfer conveyor a2, and the transfer conveyor a2 is driven in the transfer direction while the foamed sheet b2 is moved up and down intermittently. And while not moving up and down, the conveyer a2 is driven to slice the foamed sheet b2 by the metal wire g in the middle of the up and down direction, as shown in FIG. Foamed sheet b2 having such irregularities
This is a method of manufacturing two sheets of No. 1 and b22.
"Collection of Well-Known Conventional Techniques, Foam Molding", 57 (1982) -1
33 (3347)], hereinafter referred to as atypical slicing method), and the movement of the transport conveyor a2 and the foamed sheet b2, it is possible to form irregularities as shown in FIG.

A third method is to press the front and back surfaces of a prefabricated long and slightly thick foam sheet in a zigzag manner on both sides by a large number of pressing rods to form the entire foam sheet. This is a manufacturing method called a profile processing method in which the foamed sheet is bent in an uneven shape, and the middle of the foamed sheet in the vertical direction is cut horizontally to manufacture two foamed sheets having an uneven surface on one side.

[0006]

However, in the above-mentioned conventional technique, the first method has a limitation in the depth of the unevenness, and when the depth is increased, the unevenness also appears on the opposite surface. However, the second or third method has an advantage that the depth of the unevenness can be arbitrarily obtained, various shapes can be obtained, and the production amount can be doubled. Since the foam has closed cells, there is no skin on the dividing surface, that is, the uneven surface, the surface strength is weak depending on the application field, and it is easily soiled, so that there is a problem that the application is restricted as it is.

However, there is also a method of applying a skin by compression molding with a mold having a mold surface having the same unevenness after the uneven processing, but there are drawbacks such as size limitation and inefficiency. There were restrictions on the size, and the production efficiency was poor, and there was a problem in terms of profitability. It is also conceivable to laminate a thermoplastic resin film on an uneven surface to form a skin, but since it is the uneven surface, air entrapment and heat fusion are almost impossible, so this cannot be adopted.

The present invention solves the above-mentioned drawbacks of the prior art, manufactures a foamed sheet having irregularities by adopting a variant slicing method or a profile processing method, and further uses a simple method to form the irregular surface by post-processing. With a skin, there is no restriction on the depth of the unevenness, the foamed sheet does not deform, and it is possible to efficiently manufacture a foamed sheet with strength reinforcement of the dividing surface. The present invention has been made for the purpose of providing a method for producing a thermoplastic resin foam sheet having the above.

[0009]

According to the present invention, "a strip-shaped thermoplastic resin foam sheet having a uniform thickness is cut in a concave-convex shape in the middle in the vertical direction to be divided into upper and lower two layers, or to have a uniform thickness. A strip-shaped thermoplastic resin foam sheet is held in a concavo-convex shape, and the middle of the vertical direction is cut horizontally to divide into two upper and lower layers to form two foam sheets having a concavo-convex surface on one side. , A method for producing a thermoplastic resin foam sheet having an uneven surface with a skin, characterized by radiating heat energy to the uneven surface of the foamed sheet to melt and cool the surface ". .

That is, as a means for making irregularities on the surface of the foamed sheet, a variant slicing method or a profile machining method is adopted, and the depth of the irregularities is not limited on one surface of the sheet, and the foamed sheet is not deformed. The sheet is deformed by adopting a method of radiating heat energy to this surface as a method of attaching the skin to the uneven surface without skin so that unevenness with various shapes and sizes can be efficiently and freely formed. The main point is to efficiently and uniformly form a uniform epidermis.

Examples of the thermoplastic resin used in the present invention include polyethylene, polypropylene, and copolymers of ethylene-vinyl acetate, ethylene-propylene, ethylene α-olefin and the like, which are called thermoplastic elastomers. It can be used alone or as a mixture.
Then, a resin composition obtained by adding a polymerizable monomer, a heat stabilizer, a plasticizer, a colorant, an antistatic agent, a crosslinking accelerator, and a filler to these thermoplastic resins as necessary is used as a raw material. Is optional.

A conventionally known method can be employed for molding a foam using the above thermoplastic resin. For example, a thermoplastic resin is mixed with a thermal decomposition type foaming agent such as azodicarbonamide or N—N-dinitrosopentamethylenetetramine and charged into an extruder, and the foaming agent is decomposed in the extruder to form a foamable resin composition. And extruding it from a T-die for foaming, or impregnating a physical type foaming agent such as an aliphatic hydrocarbon or a halogenated hydrocarbon having a low boiling point with a foaming resin in advance before introducing it into an extruder. There is also a method of extruding the composition and the like.

When foaming is carried out through the crosslinking step,
When a foaming agent is mixed with a thermoplastic resin and extruded by an extruder, it is kneaded and melted at a temperature and pressure at which the foaming agent is not substantially decomposed to form a sheet, and then this sheet is irradiated with ionizing radiation. By crosslinking, and then heating to a temperature above the decomposition temperature of the foaming agent for foaming, or a temperature at which the foaming agent and the crosslinking agent are not substantially decomposed by the extruder by blending the foaming agent and the crosslinking agent in the thermoplastic resin. -A method of kneading and melting by pressure to form a sheet, then heating to the decomposition temperature of the cross-linking agent to crosslink, and further heating to a temperature above the decomposition temperature of the foaming agent to foam.

The thickness and the expansion ratio of the foamed sheet used in the present invention vary depending on the application, but generally the expansion ratio = 15.
A long product having a thickness of -50 times and a thickness of 10 to 50 mm is suitable.

In the present invention, a variant slicing method or a profile processing method is adopted as a method for cutting the foam sheet in the middle of the up-down direction in an uneven shape. Further, when a foamed sheet is formed by the atypical slicing method or profile processing method, a foamed sheet having two uneven surfaces can be obtained at the same time, but when the process moves to the next heating step, it is divided by the uneven processing. When an apparatus capable of heating the two foamed sheets continuously and simultaneously is used,
More efficient.

[0016]

In the method for producing a thermoplastic resin foam sheet having an uneven surface with a skin of the present invention, since the irregular slice processing method or the profile processing method is adopted as a means for making the surface of the foam sheet uneven, the vertical and horizontal directions of the foam sheet are There are no troublesome restrictions on the dimensions and the depth of the unevenness, and there is no deformation of the foamed sheet due to the unevenness processing.

Further, since a method of radiating heat energy to the uneven surface to melt it is adopted as a means for forming a skin on the divided surface, as compared with the case where a contact type heating means is adopted.
It is possible to efficiently and uniformly form a beautiful skin without deforming the shape of the foamed sheet, particularly the irregularities.

[0018]

1 is a schematic sectional view showing an example of a manufacturing apparatus suitable for use in the method for manufacturing a sheet of the present invention.

In FIG. 1, 1a and 1b are shown in FIG.
And a foamed sheet having an uneven surface with no skin formed by the atypical slicing method shown in (b), which is a wound body. The foamed sheet is a foamed sheet having an uneven surface as shown in FIG. 3 (d), which is obtained by cutting the upper and lower middle portions of a long and thick foamed sheet having a uniform thickness with a heated metal wire into an irregular shape. Has been made.

A heating box 2 has a heating zone formed therein by a heat source described later. On the upper wall of the heating box 2, inlets 21a and 21b of the foam sheets 1a and 1b are provided.
And the inlets 31a, 31b of the synthetic resin films 3a, 3b
And the outlets 22a and 22b of the foamed sheet 1a and the synthetic resin film 3a, and the foamed sheet 1b and the synthetic resin film 3b are opened in the lower wall facing each other. Four
Is a heat source and is composed of a plurality of far infrared ray burner groups 41, 42 and 43, respectively.

Numerals 5a and 5b are mirror-finished cooling rolls installed directly under the lower wall of the heating box 2 and each consist of two sets of pinch rolls 51a, 52a and 51b, 52b.

Example 1. A foamed polyethylene (trade name: Softlon, manufactured by Sekisui Chemical Co., Ltd.) with a foaming ratio of 30 times, having a thickness of 15 mm, is foamed with a thickness of 10 mm on the one side and a thickness of 5 mm on the other side by a modified slice processing method. Sheet 1
The wound body was divided into a and 1b. Next, while sequentially rewinding from the wound body, through the guide rolls 6a and 6b, into the heating box 2, the inlet 21 of the foamed sheets 1a and 1b.
Cooling rolls 5 introduced from a and 21b at a speed of 5 m / min, heated by an infrared ray burner group 41 (1 Kw / piece) to melt the uneven surface, and adjusted to a gap of 4 mm, respectively.
Cooled through a, 5b. As a result, a long foamed polyethylene sheet 11a having a good skin and unevenness,
11b was obtained.

Embodiment 2 In addition to the far infrared burner group 41, the far infrared burner group 4
Long polyethylene foam sheets 12a and 12b were obtained in the same manner as in Example 1 except that 2 and 43 were operated to heat both sides of the foam sheets 1a and 1b.

Example 3 High-pressure polyethylene film 3a, 3b having a thickness of 30 μm
Through the guide rolls 7a, 7a and 7b, 7b into the heating box 2 and the synthetic resin film inlet 31
a, 31b was introduced at a speed of 5 m / min and laminated on the back surface of the foamed sheets 1a, 1b, and the pinch rolls 51a and 52b were replaced with mirror finishing rolls using embossing rolls. In the same manner as in Example 2, long foamed polyethylene sheets 13a and 13b were obtained. The obtained product had the opposite side of the uneven surface with the skin reinforced by the high-pressure polyethylene films 3a and 3b, and the reinforced surface was embossed.

Example 4 A foamed sheet having a thickness of 15 mm was previously coated with 3
The high-pressure polyethylene film having a thickness of 0 μm was laminated to form the foam sheets 1a and 1b, and the pinch roll 5
Long expanded polyethylene sheets 14a and 14b were obtained in the same manner as in Example 2 except that embossing rolls were used instead of mirror-finishing rolls 1a and 52b. The obtained product had the opposite side of the uneven surface with the skin reinforced by the high-pressure polyethylene films 3a and 3b, and the reinforced surface was embossed.

[0026]

The method for producing a thermoplastic resin foam sheet having an uneven surface with a skin according to the present invention employs an atypical slice processing method or a profile processing method as means for making unevenness on the surface of the foam sheet. There are no troublesome restrictions on the vertical and horizontal dimensions and the depth of the unevenness, and there is no deformation of the foamed sheet due to the unevenness processing. Therefore, it is possible to form irregularities having various shapes and sizes, and the processing amount is doubled.

Further, since a method of radiating heat energy to the uneven surface to melt it is adopted as a means for forming a skin on the divided surface, as compared with the case where a contact type heating means is adopted.
It is possible to efficiently and uniformly form a beautiful skin without deforming the shape of the foamed sheet, particularly the irregularities. Therefore, a product having excellent surface strength and appearance quality can be obtained.

As a whole, the production cost can be reduced by improving the production efficiency, and the range of applications can be expanded. By the way, when the uneven foamed sheet without skin is attached to the mold by the irregular slice processing method or the profile processing method to form the skin on the uneven surface, the upper limit of the size is 1
While it was 000 (length) × 2000 (width) mm, in the case of the present invention, it is only limited by the width dimension of the foamed sheet at the time of extrusion molding.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an apparatus suitable for carrying out the manufacturing method of the present invention.

FIG. 2 is a schematic diagram for explaining a conventional method.

3 (a) is a front view showing a variant slicing method, FIG. 3 (b) is a side view of the same, and FIG. 3 (c) is a foam processed by the same method. It is sectional drawing which shows an example of the uneven | corrugated state of a sheet | seat, and this figure (d) is sectional drawing which similarly shows another example.

[Explanation of symbols]

1a, 1b, 11a, 11b, 12a, 12b, 13a, 13
Foamed sheet 2 Heating box 21a, 21b Foamed sheet inlet 22a, 22b Foamed sheet outlet 3a, 3b Synthetic resin film 31a, 31b Synthetic resin film inlet 4 Heat source 41, 42, 43 Far infrared burner group 5a, 5b Cooling roll 51a , 51b, 52a, 52b Pinch roll 6a, 6b, 7a, 7b Guide roll

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Claims (1)

[Claims] 1. A strip-shaped thermoplastic resin foam sheet having a uniform thickness is cut in the vertical direction in the vertical direction to be divided into two layers, or a strip-shaped thermoplastic resin foam sheet having a uniform thickness is provided. In a vertical shape, and the middle of the vertical direction is cut horizontally to divide it into upper and lower two layers to form two foamed sheets each having an uneven surface on one side, and then heat the uneven surface of the foamed sheet. Radiates energy to melt its surface,
A method for producing a thermoplastic resin foam sheet having an uneven surface with a skin, characterized by cooling.