JP5165428B2 - Laminated body - Google Patents

Description

  The present invention relates to a laminate.

Polyurethane sheets are excellent in abrasion resistance, scratch resistance, toughness, and stretchability, so they are used in various applications such as cushioning materials for product packaging, automotive exterior sheets, construction site protection sheets, and clothing fabrics. The demand has been expanding rapidly in recent years.
The polyurethane sheet is manufactured by using a polyurethane resin as a raw material and extruding it by a T-die method or an inflation method. The polyurethane sheet immediately after extrusion has an adhesive surface due to the physical properties of the polyurethane resin, and when the polyurethane sheet is molded alone, the molding process is hindered by sticking to a die. Therefore, conventionally, a polyurethane sheet is formed on a prepared release sheet to prevent sticking to a die or the like.
Thus, in the conventional method, it is necessary to prepare a release sheet separately when molding a polyurethane sheet. Moreover, in order to ensure the peelability from the polyurethane sheet, it was necessary to perform a peeling treatment such as a silicone coating on the release sheet.

As a method for producing a polyurethane sheet that does not require a separate release sheet and that does not need to be subjected to a release treatment, Patent Document 1 discloses that a polyurethane resin and a polyethylene resin are laminated by coextrusion molding, And a method for producing a laminate (composite film) composed of a polyethylene sheet (release sheet). According to this manufacturing method, since the laminated body of a polyurethane sheet and a peeling sheet can be manufactured in one process, it is not necessary to prepare a peeling sheet separately and it is supposed that a manufacturing process can be simplified. Furthermore, according to this manufacturing method, since the compatibility between the polyethylene resin and the polyurethane resin is low, it is supposed that the peelability of both layers can be secured without performing the peeling treatment.
JP 2000-335644 A

However, the laminate described in Patent Document 1 has a problem that the peelability is still insufficient. Moreover, since the said peeling sheet is colorless and transparent, visibility was not enough. In order to make the release sheet easy to visually recognize, it was necessary to color the release sheet.
This invention is made | formed in view of the said situation, Comprising: It aims at the laminated body which can peel a release sheet easily and can visually recognize a release sheet easily even if it does not color, and its manufacturing method.

In order to achieve the above object, the present invention adopts the following configuration.
(1) A laminate in which a foamed polyolefin layer and a thermoplastic polyurethane layer are laminated, and an adhesive layer is laminated on the surface of the thermoplastic polyurethane layer that is not in contact with the foamed polyolefin layer.
(2) in the bonded wear layer laminate according to detachably release layer, characterized in that it is stuck (1).
( 3 ) The laminate according to ( 1 ) or ( 2 ), wherein the adhesive layer contains a poultice.

According to the method for manufacturing a laminate of the present invention, it is possible to provide a laminate in which the release sheet can be easily peeled and the release sheet can be easily visually recognized without coloring.
The laminate of the present invention easily peels the release sheet, and the release sheet can be easily visually recognized without being colored.

  As shown in FIG. 1, the laminate 10 of the present invention is a sheet-like or tape-like laminate in which a foamed polyolefin layer 1 and a thermoplastic polyurethane layer 2 are directly laminated. Here, the foamed polyolefin layer 1 is a release sheet, and the foamed polyolefin layer 1 and the thermoplastic polyurethane layer 2 are laminated in a peelable state.

  The foamed polyolefin layer 1 is formed mainly of a polyolefin resin. Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, poly-4-methylpentene, ethylene / propylene copolymer, ethylene / butene copolymer, and the like. Among these, polyethylene is preferable because the raw materials are easily available and the processability is good.

  A large number of bubbles are formed in the foamed polyolefin layer 1 by foaming of the polyolefin resin. For this reason, the foamed polyolefin layer 1 of the laminate 10 is thick and soft, and is easily grasped by hand. Therefore, the laminate of the present invention easily peels the release sheet (foamed polyolefin layer 1) from the thermoplastic polyurethane layer 2 as compared to the hard release sheet (non-foamed polyethylene layer) described in Patent Document 1. be able to. Moreover, since the polyolefin layer 1 is milky white by foaming, it has good visibility and does not need to be colored.

The thickness of the foamed polyolefin layer 1 is not particularly limited, but is preferably 0.1 mm to 0.9 mm.
The expansion ratio of the foamed polyolefin layer 1 is preferably 1.1 to 3.0 times, and more preferably 1.2 to 2.0 times. When the expansion ratio of the foamed polyolefin layer 1 is less than 1.1 times, the foamed polyolefin layer 1 tends to be hard and is difficult to grasp by hand. Therefore, it becomes difficult to peel off the foamed polyolefin layer 1 from the thermoplastic polyurethane layer 2. If the expansion ratio of the foamed polyolefin layer 1 exceeds 3.0 times, molding becomes difficult. Here, the expansion ratio is a value determined by the equation (resin density of the olefin resin before foaming) / (density of the foamed polyolefin layer 1).

The bubbles in the foamed polyolefin layer 1 may be individual bubbles dispersed one by one, or may be open cells in which the bubbles are connected to each other.
The size of the bubbles in the foamed polyolefin layer 1 is about 10 μm to 400 μm, although there are differences depending on the type of foaming agent described later, the thickness of the foamed polyolefin layer, and the like.

The thermoplastic polyurethane layer 2 is formed mainly of a thermoplastic polyurethane resin in which a diol and an isocyanate compound are urethane-bonded.
Examples of the diol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,8-nonanediol, and dimethylolpentane. And aliphatic diols having 2 to 10 carbon atoms such as dimethylol heptane, and alicyclic diols such as diethylene glycol, dipropylene glycol, and 1,4-cyclohexanedimethanol. These diols may be used alone or in combination of two or more.

Examples of the isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, 4,4-diphenylmethane diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, 2,4. -Naphthalene diisocyanate, 4,4-diphenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 4,4-diisocyanate dicyclohexane, 4,4'-diisocyanate dicyclohexylmethane, isophorone diisocyanate and the like. These isocyanate compounds may be used alone or in combination of two or more.
Although the thickness of the thermoplastic polyurethane layer 2 is suitably determined according to the use use, 0.02 mm-0.30 mm are preferable and 0.03 mm-0.10 mm are more preferable.

Next, a method for producing the laminate 10 by directly laminating the foamed polyolefin layer 1 and the thermoplastic polyurethane layer 2 will be described.
The laminate 10 is manufactured by using the above-described polyolefin resin and the polyurethane resin as raw materials and simultaneously extruding (coextrusion molding) these resins into a sheet shape or a tube shape. As a method of co-extrusion molding, a known T-die extrusion molding method or inflation molding method can be used. The coextrusion molding is a method of obtaining a molded product by laminating a plurality of resins extruded simultaneously by a plurality of extruders inside or outside the die.

  Since the polyolefin resin and the polyurethane resin have low compatibility, the foamed polyolefin layer 1 and the thermoplastic polyurethane layer 2 are laminated in a state where they can be separated from each other. For this reason, it is not necessary to perform the conventional peeling process to the foaming polyolefin layer 1, and the laminated body 10 can be manufactured in one process.

  In forming the foamed polyolefin layer 1, the polyolefin resin is foamed with a foaming agent. The polyolefin resin may be foamed outside the die after coextrusion molding of the laminate 10 in the die, or may be foamed outside the die in advance before coextrusion molding. The expansion ratio of the foamed polyolefin layer 1 is appropriately adjusted depending on the type and amount of the foaming agent, the melting temperature, the die temperature, the die lip clearance, and the like.

Examples of the foaming agent include chemical foaming agents and physical foaming agents.
Examples of the chemical foaming agent include azo compounds such as azodicarbonamide, barium azocarboxylate, azobisisobutyronitrile, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, and hydrazocarbonamide. Organic chemical foaming agents that generate nitrogen gas typified by hydrazide compounds such as hydrazine compounds, p-toluenesulfonyl hydrazide, p, p'-oxy-bis (benzenesulfonyl hydrazide), sodium hydrogen carbonate, ammonium carbonate, hydrogen carbonate Inorganic chemical blowing agents that generate carbon dioxide gas such as ammonium, lower aliphatic hydrocarbon compounds such as propane, n-butane, i-butane, n-pentane, i-pentane and hexane, and alicyclic rings such as cyclobutane and cyclopentane Hydrocarbon compounds, benzene, Aromatic hydrocarbon compounds such as ene and xylene, lower aliphatic monohydric alcohol compounds such as methanol and ethanol, lower aliphatic ketone compounds such as acetone and methyl ethyl ketone, chloromethyl, chloroethyl, 1-chloro-1,1-difluoroethane, etc. And low-boiling halogenated hydrocarbon compounds.
Examples of the physical foaming agent include argon gas, helium gas, chlorofluorocarbon gas, carbon dioxide gas (carbon dioxide gas), and nitrogen gas. The gas in the present invention includes not only a gas state but also a fluid in a subcritical state and a supercritical state.
Among these foaming agents, a physical foaming agent that does not bleed from the laminate after production is preferably used.

Examples of the method of adding the chemical foaming agent include a method of dry blending with a raw material polyolefin resin, a method of mixing in a hopper of an extruder using a quantitative feeder, and the like.
Examples of the method of adding the physical foaming agent include a method of directly press-fitting into the central zone of the extruder cylinder and a method of introducing a polyolefin resin impregnated with the foaming agent into the extruder.
Among the physical foaming agents, when carbon dioxide gas or nitrogen gas is used, it is preferable to use an extrusion foam molding apparatus. Here, the extrusion foam molding apparatus is an extruder, a resin material extruder connected to the extruder and supplying a raw material resin to the extruder, and connected to the extruder, and a foaming agent (carbon dioxide gas or nitrogen gas). ) Is a known molding apparatus provided with a foaming agent supply means for supplying to the extruder.

The polyolefin resin used as the raw material of the foamed polyolefin layer 1 includes, as necessary, a bubble regulator, a nucleating agent, a crosslinking agent, a foaming aid, an antistatic agent, a filler, a lubricant, a stabilizer, an ultraviolet absorber, and an antioxidant. Appropriate amounts of additives such as colorants and colorants can also be blended.
The polyurethane resin used as the raw material of the thermoplastic polyurethane layer 2 is blended with an appropriate amount of an ultraviolet absorber, an anti-yellowing agent, an antistatic agent, a conductive agent, a reinforcing agent, a rust preventive, a freshness maintaining agent, etc., if necessary. You can also.

In this way, a laminate 10 in which the foamed polyolefin layer 1 (release sheet) and the thermoplastic polyurethane layer 2 are directly laminated is manufactured.
If the foamed polyolefin layer 1 is peeled from the laminate 10, a polyurethane sheet composed of the thermoplastic polyurethane layer 2 is obtained. In addition, since the adhesiveness of the plastic polyurethane layer 2 lose | disappears about 24 hours after manufacture, it is preferable that peeling of the polyolefin layer 1 is performed after 24 hours after manufacture.

Although the use of the laminated body 10 is not specifically limited, For example, the buffer material used for the packaging box 30 for product packaging as shown to FIG. 2, 3 is mentioned. The packaging box 30 is generally composed of packaging molds 30a and 30b formed of corrugated cardboard and the like, and a cushioning material made of a thermoplastic polyurethane layer 2 covering the openings 32a and 32b of the packaging molds 30a and 30b. .
As shown in FIG. 2, the cushioning material made of the thermoplastic polyurethane layer 2 is formed by attaching the thermoplastic polyurethane layer 2 side of the laminate 10 to a predetermined position of the packaging form 30a, and removing the foamed polyolefin layer 1 (peeling) from the laminate 10. Sheet). In addition, the cushioning material which consists of the thermoplastic polyurethane layers 2 is formed also in the packaging mold 30b like the packaging mold 30a. In order to affix the thermoplastic polyurethane layer 2 to the packing molds 30a and 30b, a known adhesive or adhesive tape can be used.

When using the packaging box 30, as shown in FIG. 3, first, the product 33 is placed on the thermoplastic polyurethane layer 2 (buffer material) affixed to the packaging form 30a. Next, the packaging mold 30b is overlaid on the packaging mold 30a so that the opening 32b faces downward, and then tape fixing or covering of an outer box (not shown) is performed as necessary. Since the product 33 packed in this manner is sandwiched and held between the thermoplastic polyurethane layers 2 having excellent toughness and stretchability, it can be avoided from damage caused by vibration or impact during transportation. it can.
Since the thermoplastic polyurethane layer 2 is excellent in wear resistance and scratch resistance, the packaging box 30 using the thermoplastic polyurethane layer 2 can be recycled multiple times. Moreover, since the thermoplastic polyurethane layer 2 is excellent in stretchability, it is possible to deal with products of various shapes with one type of packing box 30.

A laminate 20 in FIG. 4 is an example of the laminate of the present invention in which the foamed polyolefin layer 1, the thermoplastic polyurethane layer 2, the adhesive layer 3, and the release layer 4 are laminated in this order. The laminate 20 is formed by laminating the adhesive layer 3 on the surface of the thermoplastic polyurethane layer 2 of the laminate 10 that is not in contact with the foamed polyolefin layer 1, and further peeling the release layer on the surface of the adhesive layer 3. Manufactured by sticking 4. Here, the foamed polyolefin layer 1 and the release layer 4 are both release sheets, but are different from each other.
The adhesive agent used for the adhesive layer 3 is not specifically limited, A well-known adhesive agent can be used. Examples of the sticking agent include vinyl acetate, acrylic, urethane, and silicone. Although the thickness of the sticking layer 3 is not specifically limited, 5 micrometers-1 mm are preferable. Moreover, the material used for the peeling layer 4 is not specifically limited, The well-known peeling sheet which gave the peeling process to paper, a resin sheet, etc. can be used. Examples of the release treatment include known release treatments such as silicone treatment. Although the thickness of the peeling layer 4 is not specifically limited, 20 micrometers-2 mm are preferable.

As an example of usage of the laminate 20, a procedure for forming a polyurethane sheet made of the thermoplastic polyurethane layer 2 on the surface of an object will be described.
First, the peeling layer 4 is peeled from the laminated body 20, and the sticking layer 3 side is stuck on a target object. Subsequently, the polyurethane sheet by the thermoplastic polyurethane layer 2 can be formed in the surface of a target object by peeling the foaming polyolefin layer 1 (release sheet). The foamed polyolefin layer 1 does not need to be peeled off immediately after being attached to the object, and may be peeled off as appropriate.
As a method for attaching a polyurethane sheet to an object, in addition to the above, for example, after peeling the foamed polyolefin layer 1 from the laminate 20, the release layer 4 is peeled off and the adhesive layer 3 side is used as the object. It may be pasted.

Although the use of this laminated body 20 is not restrict | limited in particular, For example, by making the sticking layer 3 contain a poultice, the sticking compress sheet excellent in the elasticity can be provided. Note that a poultice is usually an external preparation made from a mixture of a medicine and water in a mud form or spread and formed into a cloth form (Reference: 15th Revised Japanese Pharmacopoeia) , Formulation General Rules 24. Cataplasms). As the medicinal product, known analgesics, anti-inflammatory agents and the like used for a patch sheet are used. Moreover, well-known components used for a poultice, such as glycerin, water-soluble polymer, water-absorbing polymer, and essential oil, can be mixed with the mixture. In addition, when the said mixture has desired adhesiveness, you may form the bonding layer 3 only with this mixture, without using a bonding agent separately.
In addition, the laminate 20 can be selected from a polyurethane resin that has both moisture permeability and waterproofness as a raw material for the thermoplastic polyurethane layer 2, so that it is excellent in waterproofness and stretchability, and does not stuffy adhesive plaster or side pad base material. It is possible to provide a clothing fabric having excellent waterproofness and moisture permeability.

  The laminate of the present invention is a laminate obtained by removing the release layer 4 from the laminate 20, that is, the laminate of the coextruded foamed polyolefin layer 1 and the thermoplastic polyurethane layer 2 on the thermoplastic polyurethane layer 2 side. The laminated body by which the bonding layer 3 was laminated | stacked on the surface may be sufficient.

  Between the foamed polyolefin layer 1 and the thermoplastic polyurethane layer 2, an adhesive layer that does not hinder peeling may be formed as necessary. In order to form the adhesive layer between the foamed polyolefin layer 1 and the thermoplastic polyurethane layer 2, three-layer extrusion may be performed by the above-described coextrusion molding.

  According to the method for producing a laminate of the present invention, it is possible to provide a laminate in which the release sheet is easily peeled off and the release sheet can be easily visually recognized without being colored. Moreover, the laminated body of this invention can peel a peeling sheet easily, and can visually recognize a peeling sheet easily, even if it does not color.

Next, the laminated body of this invention is demonstrated in detail using an Example.
(Examples 1-4)
As the laminate molding machine, a two-type two-layer air-cooled inflation molding machine equipped with a circular die of 150 mmφ was used for two extruders, 55 mmφ extruder (A) and 50 mmφ extruder (B).
The raw material for forming a polyolefin layer (hereinafter abbreviated as PO layer) to be a release sheet is low density polyethylene (MFR = 0.3 g / 10 min, density = 0.922 g / cm ³ ), azoazodicarboxylic What added amide (foaming agent) with the foaming agent density | concentration shown in Table 1 was used, and this was thrown into the extruder (A).
As a raw material for forming a thermoplastic polyurethane layer (hereinafter abbreviated as TPU layer), thermoplastic polyurethane (manufactured by Dainichi Seika Co., Ltd., Resamine P-4070EX) was used, and this was put into an extruder (B).

  Next, the extruder (A) was adjusted to a melting temperature of 170 ° C. to 200 ° C. to melt the PO layer material. Further, the extruder (B) was adjusted to a melting temperature of 130 ° C. to 190 ° C. to melt the raw material of the TPU layer. The raw material melted from the extruder (A) and the extruder (B) whose screws are controlled at the rotational speed shown in Table 1 is supplied to the circular die set at 195 ° C., and the PO layer and A resin tube having a two-layer structure composed of a TPU layer was coextruded at a take-up speed shown in Table 1. Then, the two-layer resin tube is inflated with air pressure until the folding diameter becomes 550 mm, and then both sides of the resin tube are cut into a sheet shape. As shown in Table 2, the total thickness of the laminate and the TPU layer thickness The laminates of Examples 1 to 4 in which the PO layer thickness and the foaming ratio of the PO layer were adjusted were obtained.

(Comparative Examples 1-4)
In the same manner as in the Examples except that azodicarbonamide was not added to the raw material for forming the PO layer, the rotational speed and take-off speed of the extruder (A) and the extruder (B) shown in Table 1 were The laminated body of Comparative Examples 1-4 shown in 2 was obtained.

(Evaluation method)
Samples were prepared by cutting the laminates of Examples 1 to 4 and Comparative Examples 1 to 4 to 50 mm × 50 mm, respectively. Peel off the PO layer of this sample by hand, “◎” for samples that are very easy to peel, “◯” for samples that are easy to peel, “△” for samples that are difficult to peel, and “×” for samples that are very difficult to peel As a result, the peelability was evaluated. The results are shown in Table 2.

(Evaluation)
As shown in Table 2, the laminates of Examples 1 to 4 in which the PO layer was foamed were easy to peel. Especially, Example 1 with a high expansion ratio and Example 4 with a thick PO layer were very easy to peel off.
On the other hand, the laminates of Comparative Examples 1 to 4 in which the PO layer was not foamed were very difficult to peel. In each example and each comparative example, there was no item corresponding to “Δ”.

It is sectional drawing which shows an example of the laminated body of this invention. It is a perspective view which shows one embodiment of the packaging box which uses the laminated body of this invention. It is a perspective view which shows the process of packing a product in the packing box using the laminated body of this invention. It is sectional drawing which shows an example of the laminated body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foam polyolefin layer 2 Thermoplastic polyurethane layer 3 Adhesion layer 4 Release layer 10, 20 Laminated body 30 Packing box

Claims (3)

A foamed polyolefin layer and a thermoplastic polyurethane layer are laminated ,
A laminate comprising an adhesive layer laminated on a surface of the thermoplastic polyurethane layer that is not in contact with the foamed polyolefin layer . The laminate according to claim 1 , wherein a release layer is detachably attached to the adhesive layer. The laminate according to claim 1 or 2 , wherein the adhesive layer contains a poultice.

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