JP2007261233A - Scratch-resistant film and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scratch-resistant film for simultaneously solving all of the disadvantages of uneasy rewinding, too strong adhesion, seasonal variation characteristics, poor release supplying property at the time of scratch resistant adhesion, use of a release-adjusting agent, difficulty in disposal caused by natural degradation of a dust-proof release film, dust-formation by itself, and poor workability with less production loss and productivity. <P>SOLUTION: The scratch-resistant film comprises a resin layer A including a thermoplastic resin containing no hydrogenated component, an adhesive layer B including a hydrogenated block copolymer resin or an olefin block copolymer resin, and a resin layer C including a biodegradable resin, wherein peel adhesion strength between the resin layer A and the adhesive layer B is 0.50 or more and peel adhesion strength between the resin B and the resin C is 0.01 to 0.10 N/cm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  When storing / moving optical articles, glass products, metal plates, other processed products, etc., they are attached to the articles etc., and the scratch-preventing film for protecting / preventing from scratches at that time, and its It relates to a manufacturing method.

  Conventionally, when it is necessary to prevent scratches on the surface of glass optical articles, metal plates and processed products thereof, plastic plates and processed products, packaging materials such as paper polyethylene film, etc., and articles to be packaged, especially glass plastics. In consideration of friction scratches with products and friction scratches due to adhesion of dust containing silicon particles during storage, a specific two-layer masking film, that is, an anti-scratch film, is applied to the necessary parts of these articles. For example, Patent Literature 1 and Patent Literature 2, Patent Literature 3, Patent Literature 4 and Patent Literature 5 disclose that they are attached so as not to occur. However, there is a drawback that just affixing the film becomes a problem. That is, in order to mask optical glass and transparent plastic plates, a laminated film having both adhesiveness and peelability is often used, but the adhesive layer is stuck on the plate side and the top is somewhat hardened. In the case of using a two-layer laminated film protected with a scratch-preventing substrate film, when the two-layer film is wound around a roll, the adhesive layer may adhere to the roll-shaped substrate layer and cannot be rewound.

  In order to prevent this adhesion at the time of winding, a styrene butadiene copolymer of a thermoplastic elastomer (for example, trade name Asahi Kasei Co., Ltd.) with a slightly lower adhesion to the adhesive layer and appropriate adhesion and releasability. Tuftec) and ethylene vinyl acetate copolymer (EVA: vinyl acetate content 20 wt%) are two-layer films, but the adhesive resin is exposed on the surface, so that the surrounding dust adheres to the adhesive layer side. There are drawbacks that cannot be prevented, which may damage the plates and articles. In order to prevent the adhesion of dust and foreign matter, a dust-proof film made of polyacrylic resin, aromatic polyester resin (PET), high-density polyethylene, etc. is pasted onto the adhesive layer film and adhered, and the three-layer structure is damaged. A method of sticking the inner adhesive layer to the article side such as the plate while peeling off the dust-proof laminate film immediately before sticking to the article that may damage the plate or article. Has been taken.

However, although the adhesion between the dust-proof film (for example, low density polyethylene) and the adhesive layer is slightly low, the peel strength from the adhesive layer (for example, Tuftec) is too strong, so the entire film including the adhesive layer is stretched. There are defects such as film unrollability that is difficult to uniformly adhere to articles that need to be prevented from being scratched, and a thermoplastic elastomer that has an adhesive layer with appropriate adhesiveness and releasability in an improved technology Styrene-butadiene copolymer (eg, trade name: Asahi Kasei Tuftec) and ethylene vinyl acetate copolymer (EVA: vinyl acetate content 20 wt%). Furthermore, the three-layer laminated film with tuft-tech in this adhesive layer is not only weak and unreliable from the low-density polyethylene of the release layer, but also has a strong seasonal variation in the adhesive property, and it adheres in summer. There is a defect that it is easy to cause peeling failure due to its strength, and if the surface of the article that requires a lot of gel to prevent scratches is a fine rough surface, the adhesive peelability is further unreliable There were drawbacks.
That is, there is a drawback that it is difficult to use as an anti-scratch film unless the balance between the conflicting properties of the adhesive layer and the dustproof release layer and the peel-off property is not appropriate. In order to solve this drawback, it is conceivable to apply a release adjusting agent to the adhesive layer side of a peeling dustproof film which is a constituent film of a laminated film that prevents scratches. However, there is a drawback that the release modifier applied when the dust-proof film is peeled off remains on the adhesive layer side and adheres to the surface of a plate or other article that needs to prevent the surface from being damaged, thereby reducing the commercial value.

Furthermore, this dustproof film is peeled off and discarded when it is stuck, but when it is discarded in landfills, a natural natural material that naturally decays with light or microorganisms is desired. Papers, paperboards, rayon nonwoven fabrics and the like are disclosed in Patent Document 1 among these natural and natural materials, but they themselves have the drawback of creating dust, but naturally have poor peelability. There were drawbacks.
Furthermore, in order to produce this three-layer scratch-preventing film, conventionally, a two-layer film having an adhesive layer on a polyolefin film is first prepared, which has a hard property and has both adhesiveness and peelability. A method of preparing a polyethylene methacrylic acid copolymer film and laminating three layers on the adhesive layer using the T-dilamation method is adopted. However, there is a drawback in that workability and productivity are poor because a method is employed in which they are prepared separately.

Japanese Patent Publication No. 05-074627 Japanese Patent Laid-Open No. 08-311419 Japanese Patent Laid-Open No. 10-006444 JP 2003-119435 A JP 2003-338918 A

  The present invention has the following disadvantages: it is not easy to rewind, the adhesive strength is too strong, the seasonal variation characteristic, the peeling unwinding property at the time of sticking to prevent scratches, the disadvantage of using a peeling regulator, the peeling dustproof film A layered scratch-proof film that simultaneously solves all of the disadvantages such as the disadvantage of difficult disposal due to the natural collapse of the product, the disadvantage of itself creating dust, the disadvantage of low workability and low productivity, and a method for producing the same The purpose is to provide.

As a result of diligent research to solve the above problems, the present inventors are expected that an adhesive resin comprising an aromatic polyester resin or a polyolefin resin which is considered difficult to adhere to and a specific block copolymer will be excessively adhered. By the way, all the above problems are surprisingly solved by adopting a biodegradable bioresin that is a polyester resin and an adhesive bioresin composed of a specific diblock rubber resin or a specific olefin block copolymer rubber resin. As a result, the present invention has been found.
That is, this invention is invention of following (1) to (5).
(1) It is composed of a resin layer A made of a thermoplastic resin containing no hydrogenated component, an adhesive layer B made of a hydrogenated block copolymer resin, and a resin layer C made of a biodegradable resin. Scratch characterized in that the peel adhesion strength between the resin layer A and the adhesive layer B is 0.041 or more and the peel adhesion strength between the resin B and the resin C is 0.02 to 0.04 N / cm Prevention film.
(2) The scratch-preventing film as described in (1) above, wherein the biodegradable resin is a polylactic acid resin.
(3) The scratch-preventing film according to (1) or (2), wherein the scratch-preventing film is produced by a lamination inflation method using a feed block lamination method.
(4) Hydrogenated block copolymer resin or olefin block copolymer resin constituting the adhesive resin is hydrogenated styrene / butadiene rubber resin, polystyrene-polyisoprene hydrogenated diblock elastomer resin, ethylene / propylene / butylene. The scratch-preventing film as described in (1) above, which is a copolymer rubber resin.
(5) The above-mentioned (1) to (4), wherein the resin layer A, the adhesive layer B, and the resin layer C are overlaid on a concentric circle in a die by a feed block method to form an inflation film. The manufacturing method of the damage prevention film in any one.

  According to the present invention, it is not easy to unwind, the adhesive strength is too strong, the seasonal variation, the scratches are not peelable when stuck to prevent scratches, the use of a release modifier, the dustproof film It was possible to provide an anti-scratch film that simultaneously solves all the disadvantages such as the disadvantage of difficult disposal due to natural collapse, the disadvantage of producing dust itself, the disadvantage of low productivity and poor productivity.

The present invention will be specifically described below.
In the scratch-preventing film of the present invention, the resin layer A, the adhesive layer B, and the resin layer C are configured in the order of layer A, layer B, and layer C. The total total thickness of the A, B, and C layers is 30 to 200 μm, and preferably 60 to 150 μm because it is easy to achieve the object of the present invention.
The thermoplastic resin constituting the resin layer A of the present invention is a thermoplastic resin containing no hydrogenated component, and is selected from, for example, polyolefin resins, acrylic resins, aromatic polyester resins, and polycarbonate resins. The resin is made of at least one kind of resin, and the proper processing temperature range is 160 to 210 ° C. The thermoplastic resin containing no hydrogenated component is a rule for distinguishing it from the hydrogenated block copolymer resin constituting the adhesive layer B. A diene component represented by butadiene is hydrogenated (hydrogenated). ) A thermoplastic resin that does not contain the component.

The polyolefin resin is a general term for aliphatic olefin polymer such as low density polyethylene, high density polyethylene (linear polyethylene), linear low density polyethylene obtained by metallocene method, and polypropylene resin.
Acrylic resin is a general term for polymethacrylic acid copolymer resins. In addition to the aromatic polyester resin called polyethylene terephthalate (PET), the aromatic polyester resin includes an aromatic polyester copolymer containing 50% by weight or less of a comonomer copolymerizable with the PET. Is included.
The thickness of the resin layer A should just be 10-100 micrometers as a damage prevention base material layer. If it is thinner than 10 μm, the effect of preventing scratches tends to decrease, and if it exceeds 100 μm, it is difficult to wind up the film, and workability tends to deteriorate, which is not preferable. Further, in the thickness relationship between the A layer and the following B layer, A / B is preferably 4/1 to 1/1, and more preferably 2/1 to 1.5 / 1.

  The thermoplastic elastomer resin constituting the adhesive layer B is a hydrogenated block copolymer resin or an olefin block copolymer. In this case, the hydrogenated block copolymer resin is conjugated with an aromatic vinyl compound. It is a hydrogenated block copolymer of a block copolymer with a diene compound. Examples of the hydrogenated block copolymer include hydrogenated styrene butadiene copolymer rubber (HSBR) and styrene ethylene butylene block copolymer rubber (SEBR). The olefin block copolymer includes ethylene propylene butylene copolymer. A combined rubber (manufactured by Prime Polymer Co., Ltd., trade name: Prime TPO) may be mentioned.

  The adhesive layer B adheres well to the resin layer A, and the resin layer C is a resin that has a property of being appropriately adhered without being fixed and having a peel-off property that is an appropriate releasability index. This appropriate peel adhesive strength is expressed in N / cm, and the peel adhesive strength between the resin layer A and the adhesive layer B is 0.50 N / cm or more, and the peel between the adhesive layer B and the resin layer C. It is preferably a scratch-resistant film characterized by having an adhesive strength of 0.01 to 0.100 N / cm. When the peel adhesive strength between the resin layer A and the adhesive layer B is less than 0.50 N / cm, the resin layer A and the adhesive layer B that should not be peeled off when the dust-proof peelable film layer C is peeled are preferably peeled off. Absent. In addition, when the peel adhesion strength between the adhesive layer B and the resin layer C is less than 0.01 N / cm, the resin layer C has already peeled off when the wound-proof film wound in a roll shape is rewound. The possibility that the protective work becomes impossible is undesirable. Further, when the peel adhesion strength between the adhesive layer B and the resin layer C exceeds 0.10 N / cm, there is a drawback that the peeling work becomes difficult.

This adhesive strength is a value obtained when the resin B and the resin C are cut into a strip of 3 cm in width and the peel adhesive strength is measured at a speed of 3 mm / 1 sec with an Instron tensile tester by peeling 180 degrees. / Cm. Regarding the adhesive strength and the adhesive peel strength, the adhesive strength between the resin layer A and the adhesive layer B must be stronger than the adhesive peel strength between the adhesive layer B and the resin layer C.
The thickness of the adhesive layer B should just be 5-30 micrometers as an adhesive peeling layer. When the thickness is less than 5 μm, the uniformity is not easily maintained when the inflation film is manufactured, and when the thickness is 30 μm or more, the uniformity is not easily maintained when the inflation film is manufactured. In addition, it is preferable that resin which comprises the adhesive layer B is resin whose appropriate range of the resin processing temperature is the range of 160-210 degreeC. The resin of the adhesive layer B is characterized in that it can be re-adhered after peeling, especially for polylactic acid biodegradable resins, and can be corrected and reused after peeling. If the number average molecular weight of the resin of the adhesive layer B is lower than 500, the resin may be peeled off and may adhere to the surface of a plate or other article that needs to prevent the surface from being scratched, thereby reducing the commercial value.

  The biodegradable resin constituting the resin layer C is the biodegradable resin of the layer constituting the dust-proof release film resin layer of the present invention, and the biodegradable resin is various biodegradable polyesters, Typically polylactic acid or succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, cyclopentanedicarboxylic acid and cyclohexanedicarboxylic acid, etc. Is usually 3 to 12 dibasic carboxylic acid and ethylene glycol, triethylene glycol, 1,4-butanediol, pentamethylene glycol, 1,8-octylene glycol, nanomethylene glycol, decamethylene glycol, etc. Is one or more dicarboxylic acids and glycols arbitrarily selected from 2-10 glycols Biodegradable aliphatic polyester obtained by dehydration condensation of alcohol or subsequent deglycolization reaction, or aromatic dicarboxylic acid having aromatic dicarboxylic acid, aliphatic glycol, and sulfonic acid metal base as a nuclear substituent. Aromatic polyester having biodegradability can be mentioned.

（式中、Ｒ₁ は炭素数１〜８の炭化水素を表し、Ｒ₂ は炭素数１〜８の炭化水素を表し、ｌは１００〜２０００の整数を表す。） One of the biodegradable aliphatic polyesters is an aliphatic polyester composed of an aliphatic diol and an aliphatic dicarboxylic acid represented by the following general formula (1).

(In the formula, R ₁ represents a hydrocarbon having 1 to 8 carbon atoms, R ₂ represents a hydrocarbon having 1 to 8 carbon atoms, and l represents an integer of 100 to 2000.)

（式中、Ｒ₃ は炭化水素１〜６の炭化水素を表し、ｘは１００〜２０００の整数を表す。）
これらの中でも、融点が７５℃以上のポリ乳酸、コハク酸などの脂肪族系ポリエステルが、接着性樹脂との接着性、剥離性、季節変動特性、透明性、強度、柔軟性といったフイルム物性に優れるので好ましい。 Another biodegradable aliphatic polyester is a polycondensation polyester of an aliphatic hydroxycarboxylic acid represented by the following general formula (2).

(In the formula, R ₃ represents a hydrocarbon of 1 to 6 hydrocarbons, and x represents an integer of 100 to 2000.)
Among these, aliphatic polyesters such as polylactic acid and succinic acid having a melting point of 75 ° C. or more are excellent in film physical properties such as adhesiveness with an adhesive resin, peelability, seasonal variation characteristics, transparency, strength, and flexibility. Therefore, it is preferable.

The polylactic acid according to the present invention, which is a polylactic acid biodegradable polyester, includes poly (L-lactic acid) in which the structural unit of lactic acid is L-lactic acid, poly (D-lactic acid) in which the structural unit is D-lactic acid, Lactic acid homopolymers such as poly (DL-lactic acid), which is a mixture (racemic) of L-lactic acid and D-lactic acid, and a small amount of copolymerizable comonomer other than lactic acid based on lactic acid. A polymer having a main component of lactic acid, such as a copolymer copolymerized at a ratio of less than 50% by weight, preferably not more than 30% by weight, more preferably not more than 10% by weight, or a mixture of these polymers.
Examples of the comonomer copolymerizable with lactic acid include 3-hydroxybutyrate, caprolactone, glycolic acid and the like. Among these, a homopolymer composed only of lactic acid is preferably used because it is excellent in transparency. As a method for polymerizing such polylactic acid, any known method such as a condensation polymerization method or a ring-opening polymerization method can be employed. For example, in the condensation polymerization method, polylactic acid having an arbitrary composition can be obtained by directly dehydrating condensation polymerization of L-lactic acid, D-lactic acid or a mixture thereof.

In the ring-opening polymerization method, lactide, which is a cyclic dimer of lactic acid, can be subjected to ring-opening polymerization using a catalyst while using a polymerization regulator or the like, if necessary, to obtain polylactic acid. Lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL-lactide composed of L-lactic acid and D-lactic acid. By mixing and polymerizing, polylactic acid having an arbitrary composition and crystallinity can be obtained.
For the purpose of increasing the molecular weight of polylactic acid, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, and an acid anhydride can be used. The weight average molecular weight of polylactic acid is usually in the range of 60,000 to 1,000,000, and if it is below this range, there is a possibility that almost no strength properties will be exhibited depending on the application, while if it exceeds this range, the melt viscosity However, it is too high, the fluidity is poor and the optimum processing temperature is easily lost, and the film forming processability is extremely inferior, and it is difficult to make a uniform film.

  On the other hand, the aromatic polyester according to the present invention as another example of a biodegradable polyester comprising an aromatic polyester is biodegradable, and preferably has an aromatic sulfonate metal base as a nuclear substituent. A polyester containing a dicarboxylic acid as one copolymerization component, more specifically, an aromatic dicarboxylic acid, an aliphatic glycol, and an aromatic dicarboxylic acid having a sulfonic acid metal base as a nuclear substituent, and optionally a fatty acid It is a polyester obtained by adding an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid and performing a polycondensation reaction between these components. The preferred composition of the aromatic polyester is 30 to 49.9 mol% of units derived from the aromatic dicarboxylic acid component, 35 to 50 mol% of units derived from the aliphatic glycol component, and has a sulfonic acid metal base as a substituent. 0.1 to 5 mol% of units derived from an aromatic or aliphatic dicarboxylic acid component, and 0 to 30 mol% of units derived from an aliphatic dicarboxylic acid or aliphatic hydroxycarboxylic acid component (where all units are The total is 100 mol%). The resulting film is a multi-component polyester in which aliphatic dicarboxylic acid or aliphatic hydroxycarboxylic acid is further added as a copolymerization component in order to impart or improve performance such as flexibility and biodegradability. May be.

As the biodegradable resin (A), a poly-3-hydroxyalkanoate-based polyester produced by a microorganism is also suitable. Polyesters produced by fermentation by microorganisms include poly-3-hydroxybutyrate, random copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate, and random copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate. Examples thereof include polymers, ternary copolymers of 3-hydroxybutyrate, 3-hydroxyvalerate, and 4-hydroxybutyrate. Mixtures of these are also used. For example, Metapolix, Inc. in the United States gives propionic acid and glucose to hydrogen bacteria, produces a random copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate by fermentation, and sells it under the trade name of Biopol. Yes.
As a copolymerization ratio of 3-hydroxybutyrate and 3-hydroxyvalerate, a copolymer having a content of 3-hydroxyvalerate of 2 to 20 mol% is desirable. Preferably, the copolymer has a content of 3-hydroxyvalerate of 5 to 15 mol%. The copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate may be used by adding a plasticizer, a stabilizer, an inorganic substance, or the like as necessary.

As the biodegradable resin (C), various aliphatic polyesters synthesized by condensation polymerization of an aliphatic dibasic acid and a dihydric alcohol are used. For example, aliphatic polyesters such as polyethylene succinate, polyethylene adipate, and polytetramethylene adipate obtained by condensation polymerization of succinic acid, adipic acid and ethylene glycol, and 1,4 butanediol are used. In addition, aliphatic polyesters synthesized from trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids, or anhydrides thereof can also be used. Mixtures of these are also used. Polylactic acid is used as the biodegradable resin (C), but aliphatic polyesters such as polyglycolic acid can also be used.
Specific examples of the material of the biodegradable resin film include linear polyester resin, polylactic acid resin, natural rubber biodegradable resin, biodegradable polycaprolactone resin, polyvinyl alcohol or a modified product thereof. Some biodegradable resins, biodegradable resins such as aliphatic polyester / polyether copolymers, and the like are mentioned. Among these biodegradable materials, it is particularly preferable to use a polylactic acid resin. Furthermore, a dye, an ultraviolet absorber, a thermal oxidation stabilizer, etc. may be added to these films as long as the effects of the present invention are not impaired, and the surface of the film is subjected to treatment such as corona treatment, plasma treatment, and sand mat processing. It may be provided in advance.

As the biodegradable resin, various biodegradable resins can be used. For example, polylactic acid, polycaprolactone, polybutylene succinate, poly (butylene succinate / adipate), poly (butylene succinate / Carbonate), polyethylene succinate, poly (butylene succinate / terephthalate), poly (butylene adipate / terephthalate), polyvinyl alcohol, polyhydroxybutyrate, modified starch, cellulose acetate and the like. Among them, polylactic acid, polybutylene succinate Poly (butylene succinate / adipate) can be used. Mixtures of these are also useful.
The thickness of the resin layer C should just be 5-30 micrometers as a dust-proof peeling layer. If the thickness is less than 5 μm, the uniformity cannot be easily maintained when producing an inflation film, and if it exceeds 30 μm, the disposal workability tends to be deteriorated. The resin layer C is preferably a resin whose appropriate resin processing temperature is in the range of 160 to 210 ° C. The fact that the appropriate processing temperature ranges of the resin A, the resin B, and the resin C are close is useful for the film formation of the feed block laminated film for both the productivity and the uniformity of the film.

  The scratch-resistant film of the present invention comprises a resin layer A made of a thermoplastic resin having no hydrogenated component, an adhesive layer B made of a hydrogenated block copolymer, and a resin layer C made of a biodegradable resin layer. It is made by a feed block method in which a film is blown over a concentric circle in a die and blown from a circular die slit. That is, in order to produce this conventional three-layer scratch-preventing film, first a two-layer film having an adhesive layer on a polyolefin film is prepared, and the polyethylene has a hard property and has both adhesive properties and peelability. A method of preparing a methacrylic acid copolymer film and pasting the adhesive layer on the adhesive layer to form three layers by the T-dilamation method is adopted. However, in the manufacturing method, both ends of the pasted width cause a product loss. Since the manufacturing method is prepared separately and the films are bonded together, there is a disadvantage that workability productivity is poor. However, the method of the present invention also eliminates the disadvantage.

The present invention will be described more specifically based on examples and the like, but the present invention is not limited to these examples and the like.
[Example 1]
Low density polyethylene resin (LDPE) (manufactured by Asahi Kasei Chemicals Corporation, trade name: M3240, MI: 4.0, density 0.932 g / cc) is used as resin layer A (base material layer), and adhesive resin (hydrogenated) Styrene butadiene rubber (made by Nippon Synthetic Rubber Co., Ltd., trade name: Dynalon 1321P, styrene content 10% by weight, specific gravity 0.89, MFR: 10) adhesive layer B (intermediate layer), release layer (dust-proof release) Polylactic acid aliphatic polyester resin of biodegradable resin (made by Showa High Polymer Co., Ltd., trade name: Bionore 3001) as resin layer C (outer layer), base layer 40 μm, adhesive layer 20 μm, release A surface protective scratch-preventing film was produced at a resin temperature of 180 ° C. by a feed block method and an inflation coextrusion molding method so that the layer had a thickness of 15 μm. Bonding processing was performed using this film while peeling the release layer from the adhesive resin layer onto the acrylic plate. This protective film adhesive resin layer can produce a three-layer laminated scratch-proof film in a pure state by avoiding dust contamination due to contact with the stabilizer and guide roll and atmosphere due to winding up as a sheet from the extruder. did it.

The adhesive peel strength of this film was such that the resin layer A and the adhesive layer B could not be measured. The adhesive peel strength between the adhesive layer B and the resin layer C was 0.03 N / cm.
The obtained scratch-preventing film of the present invention is adhered to the surface-finished acrylic resin article which needs to be prevented from being scratched while peeling off the dust-proof film, and it is not easy to unwind, and the adhesive strength is too strong. Disadvantages, defects with seasonal variation characteristics, defects with poor peel-off properties when applied to prevent scratches, defects with the use of a release modifier, defects that are difficult to dispose of due to the natural collapse of the peeling dust-proof film, and defects that themselves create dust It was a three-layer laminated film for preventing scratches, which solves all the disadvantages such as low productivity loss and poor productivity.

[Example 2]
Polypropylene resin (trade name: Wintic WFX4TA) is used as resin layer A (base material layer), adhesive resin (trade name: Dynalon 1321P) is used as adhesive layer B (intermediate layer), and release layer (dust-proof release film layer). A biodegradable polylactic acid polyester resin (trade name: Bionore 3001) is used for inflation as in Example 1 so that the resin layer C (outer layer) has a substrate layer of 40 μm, an adhesive layer of 20 μm, and a release layer of 15 μm. A surface protective film was prepared by an extrusion method. Bonding processing was performed using this film while peeling the release layer from the adhesive resin layer onto the acrylic plate. The adhesive resin layer of this protective film could be produced in a pure state by avoiding contact with the stabilizer and the guide roll and contamination by the atmosphere before being wound as a sheet from the extruder.

[Example 3]
High density polyethylene resin (HDPE) (product name: L-4470, MI 7.0, density 0.944 g / cm ³ , manufactured by Asahi Kasei Chemicals Corporation) is used as resin layer A (base material layer), and water is used as the adhesive resin. Styrene-butadiene rubber (made by Nippon Synthetic Rubber Co., Ltd., trade name: Dynalon 1321P, styrene content 10% by weight, specific gravity 0.89, MFR; 10) adhesive layer B (intermediate layer), release layer (dust-proof) Polylactic acid aliphatic polyester resin of biodegradable resin (made by Showa Polymer Co., Ltd., trade name: Bionore 3001) as resin layer C (outer layer) as base film layer 40 μm, adhesive layer 20 μm, A film for preventing scratches on the surface was produced by a T-die method at a resin temperature of 190 ° C. so that the release layer was 25 μm.
The results of evaluation using this film were almost the same as in Example 1.

[Example 4]
A high density polyethylene resin (HDPE) (manufactured by Asahi Kasei Chemicals Corporation, trade name: L-4470, MI 7.0, density 0.944 g / cm ³ ) is used as the resin layer A (base material layer), and ethylene is used as the adhesive resin. -Polopyrene block copolymer (manufactured by Polyme Polymer Co., Ltd., trade name: Prime TPOF3740, ethylene content: 4% by weight, MI: 4.5) adhesive layer B (intermediate layer), release layer ( Polylactic acid aliphatic polyester resin (made by Showa High Polymer Co., Ltd., trade name: Bionore 1001), a biodegradable resin, is used as a resin layer C (outer layer) as a dust-proof peeling film layer), a substrate layer 40 μm, and an adhesive layer 20 μm. Then, a surface protection scratch preventing film was produced at a resin temperature of 190 ° C. by a feed block method inflation co-extrusion molding method so that the release layer was 25 μm.
The results of evaluation using this film were almost the same as in Example 1.

[Comparative Example 1]
High density polyethylene resin (trade name: L-4470) as resin layer A (base material layer), adhesive resin (trade name: Dynalon 1321P) as adhesive layer B (intermediate layer), and low density polyethylene resin as release layer A surface protective film was prepared by inflation coextrusion molding in the same manner as in Example 1 so that (trade name: M1920) was a resin layer C (outer layer) with a substrate layer of 40 μm, an adhesive layer of 20 μm, and a release layer of 15 μm.
In this film configuration, the intermediate layer of the adhesive resin and the low density polyethylene (LDPE) layer of the release layer could not be peeled off.

[Comparative Example 2]
A high-density polyethylene resin (trade name: L-4470) is used as the resin layer A (base material layer), an adhesive resin (trade name: Hibler 7311) is used as the resin layer C (outer layer), the base material layer is 40 μm, and the adhesive layer is 20 μm. A surface protective film was prepared by inflation coextrusion molding. In the film having this structure, it was impossible to produce a pure pressure-sensitive adhesive layer because it was not able to be protected by dust due to contamination due to contact with a stabilizer, a guide roll, or the like, or contamination due to the atmosphere in the workplace, until the sheet was wound up.

The scratch-preventing film (masking film) of the present invention can be suitably used in the field of applications for preventing scratches on the surface of glass optical articles, metal plates and processed products thereof, plastic plates and processed products.

Claims (5)

  A resin layer A made of a thermoplastic resin containing no hydrogenated component, an adhesive layer B made of a hydrogenated block copolymer resin or an olefin block copolymer resin, and a resin layer C made of a biodegradable resin The peel adhesive strength between the resin layer A and the adhesive layer B is 0.50 or more, and the peel adhesive strength between the resin B and the resin C is 0.01 to 0.10 N / cm. And scratch-resistant film.   The scratch-resistant film according to claim 1, wherein the biodegradable resin is a polylactic acid resin.   The scratch-preventing film according to claim 1 or 2, wherein the scratch-preventing film is produced by a lamination inflation method using a feed block lamination method.   Hydrogenated block copolymer resin or olefin block copolymer resin constituting adhesive resin is hydrogenated styrene / butadiene rubber resin, polystyrene-polyisoprene hydrogenated diblock elastomer resin, ethylene / propylene / butylene copolymer. The scratch-resistant film according to claim 1, wherein the film is a rubber resin.   The resin layer A, the adhesive layer B, and the resin layer C are formed into an inflation film by superimposing them on a concentric circle in a die by a feed block method. For producing a scratch-resistant film.