JP2002285116A - Surface protecting sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a surface protecting sheet which is effectively obtained from a recycled article, causes neither tear, nor blocking when bending, does not remain of adhesive after peeling the surface protecting sheet. SOLUTION: This surface protecting sheet is characterized in that the surface protecting sheet is obtained by making a mixture comprising a polyolefin resin and recycled article of the surface protecting sheet into a substrate layer having 25-150 μm thickness, providing one side of the substrate layer with an adhesive layer and the other side with a mold release layer and the mold release layer, the substrate layer and the adhesive layer are formed by coextrusion molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface protection sheet and a method for producing the same. More specifically, the present invention relates to a surface protection sheet using a waste of the surface protection sheet generated during manufacturing or after use as a recycled product, and a method for manufacturing the same.
The surface protection sheet of the present invention is a metal plate, a painted metal plate,
When transporting, processing or curing aluminum sash, resin plate, decorative steel plate, polyvinyl chloride laminated steel plate, glass plate, etc.,
It is used to adhere to these surfaces to provide protection.

[0002]

2. Description of the Related Art Conventionally, waste is generated at the time of starting production of a surface protection sheet or at the time of finishing. Further, the surface protective sheet becomes waste when peeled after being applied in various applications. It is known that such waste is used for treatment by incineration and thermal recycling.
However, the use of the waste is not preferable from the viewpoint of reducing the environment and the generation of carbon dioxide, and the use of the waste for material recycling is being studied.

[0003] The use of the waste as material recycling is generally diverted to a molded article, and the reuse of the waste to the surface protection sheet itself has hardly been studied so far. The reason is that the solubility parameters of the base material and the adhesive material forming the surface protection sheet are different. This is because there is a problem that phase separation from the material occurs and the strength of the base material layer decreases. When the surface protection sheet is applied to a protected object such as a metal plate,
The metal plate to which the surface protection sheet is adhered is usually laminated and transported, but at this time, there is a problem that the back surfaces of the surface protection sheet are blocked by the influence of the pressure-sensitive adhesive material contained in the base material layer. In addition, when stored for a long period of time due to the influence of the adhesive material contained in the base material layer, the anchoring property of the base material layer and the adhesive layer is reduced, and adhesive residue is left on the protected object after the surface protection sheet is peeled off. was there.

As an example of material recycling of the waste, for example, Japanese Patent Application Laid-Open No. Hei 5-309971 proposes a surface protection sheet using a recycled product of the waste as an intermediate layer for forming a base material layer. . However, the intermediate layer of the surface protection sheet described in this publication has a high ratio of the adhesive material in the intermediate layer because a recycled product is used, and in a system in which the adhesive material and the base material cause phase separation. There has been a problem that the breaking strength of the base material layer and the surface protection sheet is reduced, and that when the sheet is subjected to bending or drawing, the sheet is torn, torn, or to have adhesive residue.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a surface protection sheet which utilizes a recycled product effectively. The surface protection sheet does not tear even when subjected to bending or the like, and does not cause blocking. It is an object of the present invention to provide a surface protective sheet free of adhesive residue after peeling off the surface protective sheet, and a method for producing the same.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above object can be achieved by a surface protective sheet having the following structure and a method for manufacturing the same. The invention has been completed.

That is, according to the present invention, a mixture containing a recycled product of a polyolefin resin and a surface protection sheet is used as a base layer having a thickness of 25 to 150 μm, and an adhesive layer is provided on one side of the base layer, and the other side is provided. The present invention relates to a surface protection sheet provided with a release layer on one surface, wherein the release layer, the base material layer, and the adhesive layer are formed by co-extrusion.

The surface protective sheet of the present invention uses the waste of the surface protective sheet as a recycled product in its base material layer, and can be efficiently recycled. Further, since the base layer is formed of a mixture of a recycled product and a polyolefin-based resin, the ratio of the adhesive material in the base layer can be kept low, and the thickness of the base layer falls within the above range. Since the adjustment is performed, a decrease in strength and the like can be suppressed to a minimum, and the occurrence of tears and the like can be prevented even when bending is performed. Further, it is possible to suppress a decrease in breaking strength, elongation, and the like.

Further, in the surface protective sheet of the present invention, since the base material layer contains an adhesive material derived from a recycled product, the base material layer has a slight adhesive property, Since a release layer is provided on the surface (one side), no blocking or the like occurs. Since the release layer is formed by co-extrusion, there is no need for a step of applying and drying a release agent, no need for a complicated step, and no waste during production.

Further, since the surface protective sheet of the present invention is formed by co-extrusion, the interface between the base material layer and the adhesive layer is extruded while being mixed in a molten state, so that the anchoring force is improved, Due to the effect of the adhesive material contained in the base material layer, no adhesive residue or the like occurs even when stored for a long time without lowering the anchoring property between the base material layer and the adhesive layer.

In the surface protective sheet, the adhesive layer may be made of a styrene block polymer, an olefin block polymer, an α-olefin copolymer, an ethylene-vinyl acetate copolymer or a random copolymer of styrene and a diene hydrocarbon. What was formed with the adhesive containing at least any one selected as a base polymer can be used preferably.

In the above surface protection sheet, the thickness of the release layer is preferably 1 to 40 μm.

In general, when a release agent such as a long-chain alkyl compound is applied and dried to form a release layer, the thickness of the release layer is
0. In such a thin release layer, the adhesive material contained in the base material layer easily moves when left at high temperatures such as in summer, and passes through the release agent layer. May cause mutual blocking. In particular, when the adhesive is left at a temperature equal to or higher than the melting point of the release agent, the adhesive material is more likely to move, and a blocking phenomenon is likely to occur. In the present invention, since the release layer is formed by co-extrusion molding, the release layer can be adjusted to the above range, even under a heated or pressurized environment, the pressure-sensitive adhesive material contained in the base material layer. The blocking phenomenon can be suppressed by suppressing the movement.

In the above surface protection sheet, the release layer preferably contains a polyolefin resin and a fatty acid amide. In addition, the polyolefin resin 100
It is preferable that the fatty acid amide is contained in an amount of 0.01 to 5 parts by weight based on part by weight.

Further, the present invention provides a base layer having a thickness of 25 to 150 μm from a mixture containing a polyolefin resin and a recycled product of a surface protective sheet, an adhesive layer provided on one side of the base layer, and another adhesive layer. A release layer provided on one side,
The present invention relates to a method for producing the surface protective sheet, which is formed by co-extrusion.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a surface protective sheet of the present invention has a base material layer 2 composed of a mixture containing a polyolefin resin and a recycled product of the surface protective sheet.
The adhesive layer 3 is provided on one side, and the release layer 1 is provided on the other side. The release layer 1, the base material layer 2, and the adhesive layer 3 are formed by co-extrusion molding, and FIG. 1 illustrates an example in which each of the above-mentioned layers is composed of three layers each consisting of one layer. The surface protective sheet of the present invention may be formed of a plurality of layers as long as the layer includes a release layer, a substrate layer, and an adhesive layer.

The material for forming the base material layer contains, as a main component, a mixture of a polyolefin resin and a recycled product of the surface protection sheet.

Specific examples of the polyolefin resin include:
For example, polypropylene or a propylene-based polymer such as a block-based or random-based polymer containing a propylene component and an ethylene component, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene,
Examples include ethylene-based polymers such as ultra-low-density polyethylene, and ethylene-ethyl (meth) acrylate copolymers and ethylene-methyl (meth) acrylate copolymers. One or a mixture of two or more of these polyolefin resins is used.

The recycled product of the surface protection sheet is a known surface protection sheet waste, and is generated when the surface protection sheet is manufactured or finished, or when the surface protection sheet is peeled off after finishing the work. . The structure of the surface protection sheet to be recycled is not particularly limited. For example, an ethylene / vinyl acetate resin, a polyisobutylene-based adhesive, an acrylic resin, or the like may be used on a base layer of a polyolefin resin, a polyester resin, a polystyrene resin, an acrylic resin, or the like. Examples thereof include those provided with an adhesive layer such as a pressure-sensitive adhesive, a diene rubber, a styrene-based ABA block polymer or a hydrogenated product thereof, and a styrene-butadiene rubber (SBR) or a hydrogenated product thereof. As the surface protective sheet to be a recycled product, a sheet using a polyolefin-based resin for the base material layer is particularly preferable because it suppresses a decrease in strength and tearability.

The blending ratio of the mixture of the polyolefin resin and the recycled product forming the base material layer is not particularly limited, and is appropriately adjusted depending on the type of the recycled product, the thickness of the adhesive layer, and the like. The recycled product is 100 parts by weight or less, preferably 80 parts by weight or less, more preferably 60 parts by weight or less, based on 100 parts by weight of the olefin resin. For efficient recycling, the amount of the recycled product is preferably at least 5 parts by weight, more preferably at least 10 parts by weight.

Recycled products having poor compatibility (high polarity) with the polyolefin resin (for example, those using a polyester resin such as polyethylene terephthalate as the base material layer, and those having a high styrene content of styrene A in the adhesive layer)
-B-A type block polymer) is mixed, a compatibilizer is added to stabilize the compatibility of the mixture of the recycled product with the polyolefin resin forming the base material layer, It is possible to make it difficult to cause a decrease in strength and tear during bending.

As the compatibilizer, those having a portion in the molecule that is easily compatible with the polyolefin resin and a portion that is easily compatible with the highly polar recycled product are preferable.
For example, ethylene-vinyl acetate polymer or styrene A
-BA type block polymer, styrene / olefin crystal type ABC-type block polymer, olefin crystal type CBC type block polymer, hydrogenated styrene-butadiene rubber, ethylene / acrylic copolymer polymer And the like. The selection of the compatibilizer is determined by the type of the surface protective sheet to be recycled, but it is preferable to use one having a relatively similar structure. The amount of the compatibilizer is appropriately determined according to the amount of the polar substance contained in the recycled product.

The thickness of the substrate layer is 25 to 150 μm, preferably 25 to 130 μm, and particularly preferably 30 to 120 μm. If the thickness of the base material layer is less than 25 μm, the base material may be broken or torn at the time of peeling, and if it exceeds 150 μm, the stiffness of the base material becomes large, and floating or the like is likely to occur after application.

As the material for forming the pressure-sensitive adhesive layer, those used for forming the pressure-sensitive adhesive layer of the surface protective sheet can be used without any particular limitation. Examples thereof include styrene-based block polymers, olefin-based block polymers, and α-olefin copolymers. And at least one selected from ethylene-vinyl acetate copolymers and random copolymers of styrene and diene hydrocarbons as a base polymer.

Examples of the styrene-based block polymer include styrene-based AB-polymers such as styrene / ethylene-butylene copolymer / styrene (SEBS) and styrene / ethylene-propylene copolymer / styrene (SEPS).
A type block polymer, styrene type AB type block polymer such as styrene / ethylene / butylene copolymer (SEB) or styrene / ethylene / propylene copolymer (SEP), styrene / ethylene / butylene copolymer / olefin crystal And styrene-olefin crystal type ABC-type block polymers such as (SEBC).
Olefin-based block polymers include olefin crystals, ethylene-butylene copolymers, and olefin crystals (CE
And olefin crystalline CBC type block polymers such as BC). Examples of the α-olefin copolymer include ethylene-α-olefin copolymer and propylene-α
Olefin polymers such as an olefin copolymer and an ethylene-propylene-α-olefin copolymer are exemplified. Among them, the density is 0.88 g / c from the viewpoint of the adhesive property.
m ² α-olefin copolymers are preferred. Examples of the random copolymer of styrene and a diene-based hydrocarbon include a styrene-based random copolymer such as styrene-butadiene rubber (SBR). The exemplary compound may be a hydride thereof. These may be used alone or in combination of two or more.

When forming the adhesive layer, for example, a softener, a polyolefin resin, a silicone polymer, an acrylic copolymer, a tackifier, an antioxidant, a hindered amine, etc. System light stabilizer, ultraviolet absorber, other, for example, calcium oxide,
Additives such as fillers and pigments such as magnesium oxide, silica, zinc oxide, and titanium oxide can be appropriately compounded.

The blending of a softening agent is generally effective for improving the adhesive strength. Examples of the softener include low molecular weight polyisobutylene, polybutene, polyisoprene, polybutadiene, hydrogenated polyisoprene, hydrogenated polybutadiene, and a reactive group such as an OH group, a COOH group, or an epoxy group at one or both terminals. , Derivatives, ethylene propylene rubber, process oil, naphthenic oil, castor oil, linseed oil, soybean oil, phthalate ester plasticizer, phosphate ester plasticizer, liquid aliphatic petroleum resin, etc. Alternatively, two or more kinds can be used, and the compounding amount is 100 parts by weight or less, preferably 60 parts by weight or less, and particularly preferably 40 parts by weight or less based on 100 parts by weight of the base polymer.

The addition of a tackifier is also generally effective in improving the adhesive strength. The amount of the tackifier is 100 parts by weight of the base polymer from the viewpoint of improving the adhesive strength while avoiding the problem of adhesive residue due to a decrease in cohesive strength. 80 parts by weight or less, preferably 40 parts by weight or less, and particularly preferably 20 parts by weight or less. As the tackifier, for example, aliphatic or aromatic,
Petroleum resins such as aliphatic / aromatic copolymers and alicyclics,
Coumarone indene resin, terpene resin, terpene phenol resin, alkylphenol resin, rosin resin, polymerized rosin resin, xylene resin, and also used as adhesives such as hydrides of these One or more known compounds can be appropriately selected and used.

Further, a polyolefin resin may be added to the pressure-sensitive adhesive layer for the purpose of suppressing an increase in adhesive strength. Examples of the polyolefin-based resin include those similar to those used for forming the base material layer. These may be used alone,
Two or more kinds may be used in combination. The compounding amount is 50 parts by weight or less, preferably 30 parts by weight or less, particularly preferably 20 parts by weight or less based on 100 parts by weight of the base polymer.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is usually preferably about 1 to 50 μm, particularly preferably 5 to 30 μm.

The material for forming the release layer is not particularly limited, but a material obtained by adding a fatty acid amide, a fatty acid ester, polyethyleneimine or the like to a polyolefin resin is preferable. Among these additives, fatty acid amides are preferable, and fatty acid amides having a melting point of 142 ° C. or more are particularly preferable for blocking and preventing blocking due to melting of the additives.

Examples of the fatty acid amide include ethylene bislauric amide, methylene bisstearic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, ethylene bisbehenic acid amide, ethylene bis-12-hydroxystearic acid amide, Butylene bis stearamide, hexamethylene bis stearamide, hexamethylene bis oleamide, xylylene bis stearamide, dioleyl adipamide, distearyl adipamide, dioleyl sebacic amide, distearyl sebacic amide And distearyl terephthalamide, distearyl isophthalamide, and the like.

Examples of the polyolefin resin include those similar to those used for forming the base material layer. The fatty acid amide may be contained in the base material layer.

The amount of the additive such as fatty acid amide is not particularly limited, but is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 2 parts by weight, per 100 parts by weight of the polyolefin resin.
Parts by weight are more preferred. More preferably, 0. It is 1 to 1 part by weight. Effectively blocking the polyolefin resins forming the release layer by causing the fatty acid amide added as a release component to bleed out to the release layer surface by adjusting the blending amount to 0.01 part by weight or more. Can be suppressed. If the amount exceeds 5 parts by weight, the amount of bleeding of the fatty acid amide increases, and the fatty acid amide is easily transferred to the glue surface and may be transferred to cause contamination of the adherend.

The thickness of the release layer is not particularly limited.
It is preferably 0 μm, more preferably 1 to 20 μm, particularly preferably 5 to 10 μm. By setting the thickness of the release layer to 1 μm or more, thickness unevenness during co-extrusion is suppressed, and the release layer is effectively provided to prevent blocking even in a heated or pressurized environment. When the thickness of the release layer exceeds 40 μm, the total amount of the additives is large, so that there is a tendency that contamination or peeling failure due to the transfer of the additives is likely to occur.

The surface protective sheet of the present invention comprises the release layer,
It can be manufactured by laminating the base material layer and the adhesive layer by a co-extrusion method. As a coextrusion method,
A method generally used for the production of a film or the like can be employed and is not particularly limited. In particular,
An inflation method, a T-die method, or the like can be used. The number of layers to be laminated is not particularly limited, and the release layer, the base material layer, and the adhesive layer may each be a single layer, or may have a multilayer structure as necessary.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and the like specifically showing the configuration and effects of the present invention will be described below.

Example 1 A 10 μm-thick release mold made of a mixture of 100 parts by weight of low density polyethylene (LDPE) (manufactured by Tosoh Corporation, Petrocene 190) and 0.5 part by weight of ethylenebisstearylamide (manufactured by Nippon Kasei) Layer and low density polyethylene (LDP
E) Thickness 1 consisting of a mixture of 100 parts by weight (Torosoh 190, manufactured by Tosoh Corporation) and 40 parts by weight of recycled product (1)
100 μm base material layer, 100 parts by weight of styrene / ethylene-butylene copolymer / styrene (SEBS) (Clayton G1657, manufactured by Shell Chemical Company) and hydrogenated petroleum resin (Alcon P-100, manufactured by Arakawa Chemical Co., Ltd.) 40 An adhesive layer having a thickness of 10 μm comprising a mixture of parts by weight was co-extruded with a T-die to prepare a surface protective sheet. The recycled product (1) used was the same as that of Example 1 except that the base material layer contained no recycled product.

Example 2 100 parts by weight of low density polyethylene (LDPE) (manufactured by Tosoh Corporation, Petrocene 190) and ethylene bisstearylamide (manufactured by Nippon Kasei Co., Ltd.) A 10 μm-thick release layer composed of 5 parts by weight of a mixture;
E) Thickness 1 consisting of a mixture of 100 parts by weight (Torosoh 190, manufactured by Tosoh Corporation) and 10 parts by weight of recycled product (2)
100 μm base material layer, 100 parts by weight of styrene / ethylene-propylene copolymer / styrene (SEPS) (Septon 2063, manufactured by Kuraray Co., Ltd.) and 30 parts by weight of hydrogenated petroleum resin (Alcon P-100, manufactured by Arakawa Chemical Co., Ltd.) A 10 μm-thick adhesive layer comprising the mixture of parts was co-extruded with a T-die to prepare a surface protection sheet. The recycled product (2) used was a surface protection sheet in which a base material layer was a 38 μm-thick polyethylene terephthalate base material (Lumirror, manufactured by Toray Industries Co., Ltd.) and an acrylic pressure-sensitive adhesive of 5 μm was attached.

Comparative Example 1 A surface protection sheet was prepared in the same manner as in Example 1 except that no release layer was provided.

Comparative Example 2 A surface protection sheet was prepared in the same manner as in Example 1 except that the thickness of the base material layer was changed to 20 μm.

Comparative Example 3 A surface protection sheet was prepared in the same manner as in Example 2 except that no release layer was provided. Immediately apply a long-chain alkyl back surface treatment agent (manufactured by Yushi Co., Ltd., Piroyl) dissolved in a toluene solution to a surface protection sheet prepared by extruding a base layer and an adhesive layer in two layers, and then dry the surface. A 0.05 μm release layer was provided on the protective sheet.

Comparative Example 4 The procedure of Example 2 was repeated, except that the adhesive layer was formed of only the recycled product (2).

Evaluation Test The surface protection sheets obtained in Examples and Comparative Examples were subjected to the following tests. Table 1 shows the evaluation results.

(Blocking Property) SUS30 obtained by subjecting the surface protective sheets obtained in Examples and Comparative Examples to a # 400 polishing treatment.
(4) Ten sheets were stuck on both surfaces of a metal plate, and ten sheets were overlapped so that the release layer of the surface protective sheet was in contact with the metal sheet, and the state of blocking after storage at 60 ° C. for one month under pressure was observed. .

(Bender workability) The surface protection sheets obtained in Examples and Comparative Examples were subjected to # 400 polishing treatment to a thickness of 1 mm.
Of SUS304 metal plate of V width 12mm
Then, the state of tearing of the substrate when bendering was performed was observed.

(Glue residue) When the surface protective sheets obtained in Examples and Comparative Examples were applied to a mirror-finished SUS304 metal plate, left at 80 ° C. for 3 months, and then peeled off at 0 ° C. Was examined for the presence of adhesive residue.

[0048]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a surface protection sheet of the present invention.

[Description of Signs] 1 Release layer 2 Base layer 3 Adhesive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/20 C08K 5/20 C08L 23/00 C08L 23/00 C09J 109/06 C09J 109/06 123/00 123/00 131/04 131/04 153/00 153/00 (72) Inventor Shinichi Takada 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Keiji Hayashi Ibaraki, Osaka 1-1-2, Shimohozumi Ichito F-term in Nitto Denko Corporation (reference) 4F071 AA18 AA19 AA20 AC12 AE11 AE22 BA01 BB06 BC01 BC02 4F100 AK03A AK03B AK06 AK12C AK42 AK48B AK68C BA03 BA07 J10 JBJL10 JE JB GBL YY00B 4J002 BB031 BB071 BB121 BP021 EP026 FD166 FD206 4J004 AA06 AA07 AA09 CA04 CA06 CB03 CC04 CC05 DA02 FA04 4J040 CA081 DB051 DE031 DM011 DM021 HC11 JA09 JB09 LA06 MA02 MA05 MA10 MA11 MB 03 MB05 NA06 PA33

Claims (6)

[Claims] 1. A mixture containing a recycled product of a polyolefin resin and a surface protection sheet is coated with a thickness of 25 to 150 μm.
m base material layer, an adhesive layer is provided on one side of the base material layer, a surface protection sheet provided with a release layer on the other side, the release layer, the base layer and A surface protection sheet, wherein the adhesive layer is formed by co-extrusion molding. 2. The pressure-sensitive adhesive layer, wherein the adhesive layer is at least one selected from a styrene-based block polymer, an olefin-based block polymer, an α-olefin copolymer, an ethylene-vinyl acetate copolymer, and a random copolymer of styrene and a diene-based hydrocarbon. The surface protection sheet according to claim 1, wherein the surface protection sheet is formed of a pressure-sensitive adhesive containing one kind as a base polymer. 3. The surface protective sheet according to claim 1, wherein the release layer has a thickness of 1 to 40 μm. 4. A release layer comprising a polyolefin resin and a fatty acid amide.
4. The surface protective sheet according to any one of 3. 5. The surface protection sheet according to claim 4, wherein the fatty acid amide is contained in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polyolefin resin. 6. A mixture containing a polyolefin-based resin and a recycled surface protection sheet, and having a thickness of 25 to 15
The base layer having a thickness of 0 μm, the adhesive layer provided on one side of the base layer, and the release layer provided on the other side are formed by co-extrusion. A method for producing the surface protective sheet according to the above.