KR102494761B1 - Multilayer sheet and manufacturing method thereof - Google Patents

Abstract

The present invention provides a multi-layered sheet sequentially comprising a release paper, an acrylic pressure-sensitive adhesive layer, an acrylic primer layer, and an acrylic support layer.

Description

Multi-layer sheet and its manufacturing method {MULTILAYER SHEET AND MANUFACTURING METHOD THEREOF}

The present invention relates to a multilayer sheet and a method for manufacturing the same.

The coating film for advertising is attached to the top of the advertising printing film and is used for the purpose of protecting the printed surface and changing the surface light. For this purpose, transparency and weather resistance are required above all else.

For example, these days, back-lit awning fabric for advertising (hereinafter referred to as 'PVC flexible fabric') is made of PVC (Poly Vinyl Chloride) as a main component, which is lighter and more flexible, and thus has excellent processability and a more beautiful appearance. ) has been developed and used in various ways. Such PVC flexible fabric is usually made into a PVC film by melting PVC resin, and then the PVC film is laminated to a polyester fabric by a calender, or resin powder is dispersed in a plastic material to make plastic. A plastisol was prepared and the plastisol was prepared by knife coating on a polyester fabric.

However, PVC flexible fabrics manufactured by these methods are easily contaminated around the edges when the final product is used as an advertising fabric because PVC resin is attached to the fabric by a calender or knife, and polymethyl methacrylate as a surface treatment agent Since a solution in which a mixture of polymer and polyvinyl acetate was dissolved in a solvent was used, yellowing of acrylic and vinyl may occur due to photoaging.

In addition, since coating with a thickness of several tens of μm on the surface of a thick sheet having a thickness of 100-1000 μm is usually inappropriate due to the inefficiency of the continuous coating process due to the drying speed and thickness, the material to be coated using an adhesive or pressure-sensitive adhesive It is preferable to make a film and laminate or laminate and fuse.

However, multi-layer sheets including adhesives or pressure-sensitive adhesives and a PVC support layer known so far have limitations in providing weather resistance and transparency as well as stain resistance and scratch resistance.

Therefore, in order to solve the above problems, it is necessary to develop a multilayer sheet having excellent weather resistance and high transparency.

Korean Registered Patent No. 10-0092537

The present invention provides a multi-layer sheet.

The present invention provides a multi-layered sheet sequentially comprising a release paper, an acrylic pressure-sensitive adhesive layer, an acrylic primer layer, and an acrylic support layer.

The multilayer sheet according to the present invention can improve weather resistance and maximize high transparency.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the contents of the above-described invention, so the present invention is limited to those described in the drawings. It should not be construed as limiting.
1 is a cross-sectional view of a multilayer sheet according to the present invention.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention.

The terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to explain their invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

The multi-layer sheet 100 according to the present invention with reference to FIG. 1 is a multi-layer sheet sequentially including a release paper 110, an acrylic pressure-sensitive adhesive layer 120, an acrylic primer layer 130, and an acrylic support layer 140, The acrylic support layer 140 includes at least one of a polymethylmethacrylate (PMMA)-based acrylic film and a fluorine-coated acrylic film, and the acrylic primer layer 130 includes an acrylic-modified polyol, an epoxy resin, and an isocyanate curing agent. It is formed by an acrylic primer composition comprising

The multi-layer sheet according to the present invention can remarkably improve weather resistance and transparency by including an acrylic film with strong weather resistance, an acrylic pressure-sensitive adhesive layer, and an acrylic primer layer.

Hereinafter, the present invention will be described in more detail.

<Lee Hyungji>

According to the present invention, the release paper may use conventionally used paper or PET (Polyethylene Terephthalate) film. However, since the transparency of the coating film may vary depending on the type of release paper, it is good to select and apply the type of release paper.

According to the present invention, the release paper may include a polyethylene coating part, a silicone coating part, or one or more kinds of coating parts thereof on paper. In addition, the type of paper may be release paper having a surface roughness (Rz) of 0.01 to 2 μm compared to commonly used white paper. When the surface roughness is less than 0.01 μm, adhesion with an acrylic pressure-sensitive adhesive layer described later may decrease, and when the surface roughness exceeds 2 μm, transparency (transmittance) of the final multilayer sheet may decrease. The polyethylene coating on the release paper prevents silicone from penetrating the release paper during silicone coating, and the silicone coating can prevent adhesion between the sheet and the release paper by using the property of pushing the acrylic pressure-sensitive adhesive layer. Specifically, the release paper may sequentially include paper, a polyethylene coating part, and a silicone coating part.

<Acrylic pressure-sensitive adhesive layer>

The acrylate monomer included in the pressure-sensitive adhesive composition for forming the acrylic pressure-sensitive adhesive layer according to the present invention is specifically 2 selected from butyl acrylate, methyl methacrylate, ethyl acrylate, ethylhexyl acrylate, butyl methacrylate, etc. It may contain more than one species of monomers. For example, butyl acrylate, methyl methacrylate and butyl methacrylate monomers may be used as the monomer. As the amount of butyl acrylate, a monomer with a low glass transition temperature, increases, it is soft and effective in improving adhesive strength, and as the amount of methyl methacrylate, which has a high glass transition temperature, increases, the cohesive strength of the pressure-sensitive adhesive layer improves, so the use of both Proportion can be adjusted appropriately

The acrylic pressure-sensitive adhesive composition includes 80 to 95 parts by weight of butyl acrylate, 3 to 10 parts by weight of methyl methacrylate, 2 to 5 parts by weight of butyl methacrylate, 5 to 10 parts by weight of acrylic acid, and 1 to 5 parts by weight of a polymerization initiator. A polymerized acrylic copolymer may be included. For example, the composition of the acrylic monomer may include 85 to 90 parts by weight of butyl acrylate, 6 to 7 parts by weight of methyl methacrylate, and 4 to 5 parts by weight of butyl methacrylate.

The polymerization initiator included in the pressure-sensitive adhesive composition according to the present invention is not specifically limited, and may include an oil-soluble azo-based compound, a water-soluble azo-based compound, and a peroxide. In particular, in consideration of handling safety and production efficiency, azo-based compounds having no risk of generating oxygen that hinders polymerization during decomposition may be used, and in the case of polymerization by solution polymerization, oil-soluble azo compounds may be used in terms of solubility. . Specific examples of the polymerization initiator include 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4'-dimethylvaleronitrile), and 2 , 2'-azobisisobutyronitrile may include one or more.

The polymerization initiator may be included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive composition.

The acrylic copolymer may have a glass transition temperature (Tg) of -40 to 20 °C and a weight average molecular weight of 300,000 - 1,000,000 g/mol. When the glass transition temperature of the acrylic copolymer is less than -40°C, the bonding strength of the pressure-sensitive adhesive layer is lowered, and thus the adhesion to the base film during coating may be lowered. In addition, when the glass transition temperature of the acrylic copolymer exceeds 20 ° C., the solubility in the solvent is lowered, and there may be problems such as generation of gel during coating of the pressure-sensitive adhesive composition. In addition, if the weight average molecular weight of the acrylic copolymer is less than 300,000 g/mol, the bonding strength of the pressure-sensitive adhesive layer may be lowered, resulting in insufficient adhesion to the base film during coating. On the contrary, the weight average molecular weight of the acrylic copolymer exceeds 1,000,000 g/mol. Even so, the solubility in the solvent is low, and there may be problems such as generation of gel during coating of the pressure-sensitive adhesive composition.

The acrylic pressure-sensitive adhesive composition may further include a curing accelerator or dispersant, if necessary. There is no particular limitation on the method for preparing the acrylic pressure-sensitive adhesive composition, and it may be performed using conventional equipment according to a conventional method for preparing a polymer composition. For example, after uniformly mixing an acrylic copolymer and an ultraviolet curable acrylate compound with a solvent, a photoinitiator, a thermal curing agent, and other optional components may be added and mixed, but may be prepared by adding, but is not limited thereto.

<Acrylic primer layer>

According to the present invention, by including an acrylic primer layer on the acrylic support layer, the multi-layer sheet can provide a multi-layer sheet with excellent adhesive strength, and can maintain excellent weather resistance and transparency even when exposed to an external environment for a long period of time.

For example, the acrylic primer layer may be prepared by adding 100 parts by weight of an acrylic modified polyol and 2 to 10 parts by weight of an epoxy resin, and may be a two-component composition including a curing agent containing an isocyanate-based curing agent. .

The acrylic-modified polyol resin of the present invention has a solid content of 40 to 80% by weight, a weight average molecular weight of 5,000 to 50,000, a hydroxyl value of 40 to 180 mg KOH/g, an acid value of 3 to 30 mg KOH/g, and a glass transition temperature (Tg). It may be 30 to 60 ° C.

The acryl-modified polyol resin may use a lactone-modified acryl monomer and a novel functional acryl monomer, thereby significantly improving scratch resistance and improving appearance.

In addition, the monomers used in the acrylic-modified polyol resin are specifically, 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2- Hydroxybutyl (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, ethylene glycol di(meth)acrylate and 1,6-hexanediol di( It may include an acrylic monomer having at least one hydroxyl group such as meth)acrylate and a mixture thereof. The acrylic monomer having at least one hydroxyl group is copolymerized with a monomer such as styrene, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate or a mixture thereof It can be.

In the acrylic-modified polyol resin, scratch resistance may be deteriorated when the hydroxyl value is less than 40 mg KOH/g, and coating workability may be deteriorated when the hydroxyl value exceeds 180 mg KOH/g. In addition, if the acid value is less than 3 mg KOH/g, the adhesion of the coating film may deteriorate, and if the acid value exceeds 30 mg KOH/g, the coating film may become too hard.

In addition, the acrylic primer composition may include an epoxy resin having two or more epoxy groups in order to secure excellent adhesion. At this time, the content of the epoxy-based resin having two or more epoxy groups may play an important role in determining the physical properties of the coating film. Epoxy-type resin should just contain 2 or more epoxy groups in 1 molecule, and also includes various resins containing an epoxy group as a functional group as well as a polyfunctional epoxy resin. Although not particularly limited as the epoxy resin, for example, novolak type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type, cresol novolak type, and bisphenol novolak type, aliphatic epoxy resins etc. can be mentioned. In addition, these epoxy-type resins can be used individually or in combination of 2 or more types as needed.

The epoxy equivalent of the epoxy-based resin is preferably 150 to 1000 g/eq. By setting the epoxy equivalent to 150 g/eq or more, the adhesiveness to an acrylic film or the like can be made effective. In addition, by setting the epoxy equivalent to 1000 g/eq or less, the curing reaction can be prevented from deteriorating and the thermosetting property can be prevented from deteriorating.

The mixing ratio of the acrylic-modified polyol resin and the epoxy-based resin may be 1:0.02 to 0.1 weight ratio. For example, when the content of the epoxy-based resin having two or more epoxy groups is less than the above ratio, mechanical properties and adhesion may be deteriorated, and when the ratio is exceeded, corrosion resistance may be deteriorated.

In addition, the acrylic primer composition contains 3 parts by weight to 10 parts by weight of a sagging control agent having a solid content of 50% by weight based on 100 parts by weight of acrylic-modified polyol in order to prevent dripping and to be easily coated on curved areas. can be used as a part. A material used as the flow control agent may include a thermosetting acrylic resin containing a urea group.

The acrylic primer composition may include a silicone-based surface control agent having a polyether-modified dimethyl polysiloxane structure in order to impart leveling and slip properties. The silicone-based surface conditioner used in the present invention may be used in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the acrylic-modified polyol. If it exceeds the part, it may adversely affect the adhesion between layers during re-coating.

In addition, the acrylic primer composition can control the diffusion effect of the primer by including a curing agent, and can improve the adhesion of the primer layer. The curing agent may include an isocyanate-based curing agent having a solid content of 90% by weight, specifically, an isocyanate (hexamethylene diisocyanate) curing agent.

The curing agent part including the isocyanate-based curing agent may include a curing agent alone or a curing agent and a solvent. In addition, in the acrylic primer composition, the curing agent may be included in an amount of 10 to 15 parts by weight based on 85 to 90 parts by weight of the resin part. If the content of the curing agent is less than 10 parts by weight, acid resistance may decrease, and if it exceeds 15 parts by weight, scratch resistance may decrease.

The acrylic primer composition of the present invention may further include a solvent, and the solvent is used to maintain the thickness of the coating film and improve painting workability, and includes n-heptane, toluene, xylene, petroleum-based compounds and n -Non-polar solvents such as hexane Ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, dibasic esters, 3-methoxy butyl acetate, amyl acetate, butyl glycol acetate, methyl ethyl ketone, methyl isobutyl At least one of polar solvents such as ketone, acetone, diisobutyl ketone, isophorone and cyclohexanone, and a mixture of the non-polar solvent and the polar solvent may be appropriately selected and used according to the properties or volatilization rate of the resin.

In addition, the acrylic primer composition may further include various additives such as a leveling agent and a slip agent, if necessary.

<Acrylic support layer>

Conventionally, when PVC (Poly Vinyl Chloride) is used as a main component, staining is easy, and yellowing may occur due to photoaging of acrylic and vinyl, and there is a limit to implementing weather resistance and transparency.

On the other hand, in the acrylic support layer according to the present invention, the polymethyl methacrylate (PMMA) is a synthetic resin using methyl methacrylate (MMA) monomer as a main raw material, and has the best transparency among all plastics and has high surface hardness and thus excellent scratch resistance. do. In addition, it has excellent weather resistance as well as excellent chemical resistance, surface gloss, and adhesiveness.

The PMMA acrylic film may include, for example, a copolymer of methyl methacrylate and acrylate and an acrylic rubber in a weight ratio of 95 to 99: 1 to 5, and the copolymer of methyl methacrylate and acrylate may have a weight average molecular weight of 50,000 to 100,000 g/mol. In addition, the acrylic support layer may include a fluorine-coated acrylic film, and specifically, may be a fluorine-coated acrylic film in which a fluoropolymer is coated on the acrylic film, specifically, the PMMA. In the case of using the fluorine-coated acrylic film, performance such as stain resistance and scratch resistance may be further improved.

The fluorine coating may include a fluoropolymer having an amorphous region and having a crystallinity of less than 60%. For example, a fluoropolymer having an amorphous region may have a crystallinity of 10% to 50%. In the present specification, the term "crystallization degree" means the percentage (by weight) of the crystalline region included in the total resin, which can be measured by a known method such as differential scanning calorimetry. For example, crystallinity measurement of a fluoropolymer by differential scanning calorimetry can be performed as follows. The heating rate is set at 10 ° C per minute, the heat of fusion (Hf) is measured in the second heating process, and based on the heat of fusion of polyvinylidene fluoride having 100% crystallinity (Hf = 105 J / g) , the crystallinity of each polymer can be obtained.

The fluoropolymer having the crystallinity as described above is prepared by copolymerizing an appropriate comonomer to release the regular element arrangement of the fluoropolymer or by polymerizing the polymer in the form of a branched polymer. can do. In addition, the crystallinity of the fluoropolymer coating layer can also be achieved through mixing of two or more fluoropolymers.

For example, the fluoropolymer is hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE), tetrafluoroethylene (TFE), trifluoroethylene, hexafluoroisobutylene, perfluorobutylethylene , perfluoromethylvinyl ether (PMVE), perfluoro hexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole (PDD) and perfluoro-2-methylene-4 It may be polyvinylidene fluoride (PVDF) containing at least one comonomer selected from the group consisting of -methyl-1,3-dioxolane (PMD) in a polymerized form.

In embodiments of the present invention, the fluoropolymer may have a weight average molecular weight of 50,000 to 1,000,000 g/mol. The weight average molecular weight is a value in terms of standard polystyrene measured by GPC (Gel Permeation Chromatograph). In embodiments of the present invention, by adjusting the weight average molecular weight of the resin as described above, it is possible to secure excellent solubility and other physical properties.

According to the present invention, when the acrylic support layer is coated with fluorine, the acrylic film, PMMA: the fluorine coating layer, may have a thickness ratio of 1:2 um to 3 um. When an acrylic support layer that satisfies the above range is implemented, weather resistance as well as stain resistance and scratch resistance may be further improved.

<Multilayer Sheet>

In the multilayer sheet according to the present invention, the thickness of the acrylic primer layer and the acrylic support layer may be 1 to 5 μm and 70 to 80 μm, respectively. In the multilayer sheet according to the present invention, the thickness of the release paper and the acrylic pressure-sensitive adhesive layer may be 150 to 170 μm and 20 to 30 μm, respectively.

Specifically, the thickness ratio of the acrylic pressure-sensitive adhesive layer, the acrylic support layer, and the acrylic primer layer may be 2.5 to 4:0.05 to 0.4:1, and when the release paper is included, the thickness ratio of the release paper, the acrylic pressure-sensitive adhesive layer, the acrylic primer layer, and the acrylic support layer It may have a thickness ratio of 5 to 7:2.5 to 4:0.05 to 0.4:1. In the case of manufacturing a multi-layer sheet satisfying the above thickness range, weather resistance and transparency may be excellent. If the thickness range of the multi-layer sheet is out of the above range, weather resistance and transparency may be deteriorated, and painting workability and physical property effects of the multi-layer sheet may be impaired.

The method for manufacturing the multi-layer sheet may include the following examples.

A method for manufacturing a multi-layer sheet according to the present invention is to add an acrylic modified polyol, an epoxy resin and an isocyanate curing agent to one side of an acrylic support layer including at least one of a polymethyl methacrylate (PMMA) based acrylic film and a fluorine-coated acrylic film. It can be prepared by forming an acrylic primer layer by the containing acrylic primer composition, forming an acrylic pressure-sensitive adhesive layer by using the acrylic pressure-sensitive adhesive composition on a release paper, and then laminating them.

Alternatively, an acrylic pressure-sensitive adhesive layer is formed on a release paper with an acrylic pressure-sensitive adhesive composition, and an acrylic primer layer is formed on the acrylic pressure-sensitive adhesive layer with an acrylic primer composition, and then a polymethyl methacrylate (PMMA)-based acrylic film and a fluorine-coated coating are applied. It may be formed by sequentially stacking acrylic support layers including one or more types of acrylic films.

Specifically, an acrylic pressure-sensitive adhesive composition and an acrylic primer composition may be prepared to form the acrylic pressure-sensitive adhesive layer and the acrylic primer layer, respectively, and the specific types and methods thereof are as described above.

For example, the manufacturing method of the multilayer sheet according to the present invention is a methacrylate and acrylate copolymer (molecular weight: Mw 50,000 - 100,000 g / mol) 98-99% and methyl methacrylate acrylic rubber (Rubber) 1-2 It is possible to prepare a support layer of a PMMA-based acrylic film having a thickness of 70 to 80 μm composed of %. Thereafter, the acrylic primer composition may be coated on the support layer to form an acrylic primer layer having a thickness of 1 to 5 μm.

In the manufacturing method of the multi-layer sheet, the coating method that can be performed in each step is not particularly limited, for example, bar coating, comma coating, slot die coating , gravure coating, spray coating, and the like.

After the coating process, a drying or curing process may be further performed, and the curing method is not particularly limited. For example, photocuring or thermal curing alone, or photocuring followed by thermal curing or thermal curing followed by photocuring may be performed.

When applied to a coating film for advertising using the multi-layer sheet according to the present invention, weather resistance, scratch resistance and stain resistance can be improved, as well as satisfactorily high transparency can be realized. In particular, in the case of using a multi-layer sheet including the acrylic pressure-sensitive adhesive layer, the acrylic support layer, and the acrylic primer layer, weather resistance and high transparency can be remarkably improved. Such a multi-layer sheet may be variously used as a lighting board, a billboard, or a lighting sheet.

Hereinafter, examples will be described in detail to explain the present invention in detail. However, the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example

Example 1

Preparation of acrylic pressure-sensitive adhesive composition

85 parts by weight of butyl acrylate, 6 parts by weight of methyl methacrylate, 4 parts by weight of butyl methacrylate, 4 parts by weight of acrylic acid, 2,2-azobis as a polymerization initiator in a four-necked flask equipped with a thermometer and a condenser under a nitrogen atmosphere (2,4-dimethyl valeronitrile (2,2-azobis (2,4-dimethyl valeronitrile) AIBN) 1 part by weight was mixed with an acrylic resin containing an acrylic copolymer was prepared.

An adhesive composition consisting of 98.9 parts by weight of the acrylic resin and 1.1 parts by weight of an isocyanate (hexamethylene diisocyanate) curing agent was prepared.

Preparation of acrylic primer composition

100 parts by weight of an acrylic-modified polyol resin (solid content of 40 to 80% by weight, molecular weight of 5,000 to 50,000) and 3 parts by weight of a bisphenol A type epoxy resin were placed in a container and mixed at low speed using a stirrer. Thereafter, a resin part was prepared by adjusting the viscosity to 59 to 65 KU by additionally using commonly available additives (ultraviolet ray absorbent, surface conditioner, curing accelerator) and diluent. Then, an acrylic primer composition was prepared by mixing 10 parts by weight of an isocyanate (hexamethylene diisocyanate) curing agent with respect to 90 parts by weight of the resin part. The viscosity of the prepared acrylic primer composition was adjusted to 15 - 18 seconds (FORD CUP # 4/20 ° C).

Manufacture of multilayer sheets

A support layer of a PMMA film having a thickness of 75 μm composed of 98-99% of methacrylate and acrylate copolymer (molecular weight: Mw 50000 - 100000g/mol) and 1-2% of methyl methacrylate acrylic rubber was formed. . The acrylic primer composition was coated on the support layer through gravure printing to form an acrylic primer layer having a thickness of 2 to 3 μm.

Then, on a release paper having a thickness of 160 μm containing silicon compound coating part / polyethylene coating part / paper (snow white paper having a surface roughness of 0.1 μm) at a thickness ratio of 1: 2 μm to 3 μm: 5 μm to 10 μm The acrylic pressure-sensitive adhesive composition was coated to form an acrylic pressure-sensitive adhesive layer having a thickness of 25um.

Then, the support layer and the pressure-sensitive adhesive layer were laminated so as to face each other to obtain a multi-layer sheet in which the release paper, the acrylic pressure-sensitive adhesive layer, the acrylic primer, and the acrylic support layer were sequentially laminated.

Example 2

In the manufacture of the multi-layer sheet, a multi-layer sheet was obtained in the same manner as in Example 1, except that a PVDF-coated acrylic film was used instead of the PMMA acrylic film.

Example 3

A multilayer sheet was obtained in the same manner as in Example 1, except that a release paper having a thickness of 160 μm including a silicone compound coating portion/polyethylene coating portion/paper (surface roughness of 4.0 μm) was used.

Comparative Example 1

A multilayer sheet was obtained in the same manner as in Example 1, except that the primer layer was not applied.

Comparative Example 2

A multilayer sheet was obtained in the same manner as in Example 1, except that the support layer was formed using a PVC film.

Comparative Example 3

A multi-layer sheet was obtained in the same manner as in Example 1, except that a support layer was formed using a PVC film, a primer layer was not applied, and normal white paper (surface roughness: 5.0 μm) was applied as a release paper. .

Experimental example

Weather resistance and high transparency were measured as follows using the coating films obtained according to the above Examples and Comparative Examples, and evaluated according to the following evaluation criteria, and the results are shown in Table 1 below.

weatherability test

Using Atlas' CB165-XWA type xenon-arc lamp (320nm), the sample size was 15 X 4cm and the number of samples was 20.

Weatherability was measured after 1,000 hours at 83°C and 60% humidity.

Transparency test

A sample sampled in a size of 10 cm X 10 cm is placed vertically on a haze meter (AUTOMATIC DIGITAL HAZEMETER, manufactured by Nippon Densoku Co., Ltd., Japan), and light with a wavelength of 400 - 700 nm is transmitted in a direction perpendicular to the vertically placed sample. values were measured.

At this time, the haze value was calculated from Equation 1 below.

<Equation 1>

Haze (%) = (1 - amount of scattered light / total amount of light transmitted) × 100

adhesion test

The prepared multi-layer sheet was cut into pieces of 150 mm × 25 mm in size, each of these pieces was adhered to a SUS304 film, left for 1 hour under conditions of 20 ° C and 65% RH, and then peeled at 300 mm / min. The adhesive force (peel force) was measured under the measurement conditions of speed and peel angle of 180°.

item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 weatherability ◎ ◎ ◎ ○ △ △ Transparency (%) 2.1 2.3 5.5 2.2 10.8 12.8 Adhesion (N/inch) 18.0 17.0 15.0 11.0 13.5 10.0 X: Poor △: Normal ○: Good ◎: Excellent

100: multi-layer sheet
110: release paper
120: acrylic adhesive layer
130: acrylic primer layer
140: acrylic support layer

Claims (9)

A multi-layer sheet sequentially comprising a release paper, an acrylic pressure-sensitive adhesive layer, an acrylic primer layer, and an acrylic support layer,
The acrylic primer layer is formed by an acrylic primer composition containing an acrylic modified polyol resin, an epoxy resin and an isocyanate curing agent,
The acrylic-modified polyol resin has a hydroxyl value of 40 to 180 mg KOH / g and an acid value of 3 to 30 mg KOH / g,
The epoxy-based resin is an epoxy equivalent of 150 to 1000 g / eq, a multi-layer sheet.
The method of claim 1,
The acrylic support layer is a multi-layer sheet comprising at least one of a polymethyl methacrylate (PMMA)-based acrylic film and a fluorine-coated acrylic film.
delete The method of claim 1,
The acrylic pressure-sensitive adhesive layer comprises 80 to 95 parts by weight of butyl acrylate, 3 to 10 parts by weight of methyl methacrylate, 2 to 5 parts by weight of butyl methacrylate, 5 to 10 parts by weight of acrylic acid and 1 to 5 parts by weight of a polymerization initiator A multi-layer sheet formed of an acrylic pressure-sensitive adhesive composition.
The method of claim 1,
The release paper is a multi-layer sheet comprising a polyethylene coating, a silicone coating, or one or more coatings thereof on paper.
The method of claim 1,
The release paper has a surface roughness (Rz) of 0.01 to 2 μm.
The method of claim 2,
The PMMA-based acrylic film is a multilayer sheet comprising a copolymer of methyl methacrylate and acrylate and an acrylic rubber in a weight ratio of 95 to 99: 1 to 5.
The method of claim 2,
The fluorine-coated acrylic film is hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE), tetrafluoroethylene (TFE), trifluoroethylene, hexafluoroisobutylene, perfluoro Robutylethylene, perfluoromethylvinyl ether (PMVE), perfluoro hexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole (PDD) and perfluoro-2- A polyvinylidene fluoride (PVDF) coated acrylic film containing at least one comonomer selected from the group consisting of methylene-4-methyl-1,3-dioxolane (PMD) in a polymerized form.
The method of claim 1,
The thickness ratio of the acrylic pressure-sensitive adhesive layer, the acrylic support layer, and the acrylic primer layer is 2.5 to 4: 0.05 to 0.4: 1 multi-layer sheet.

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