JP2001354800A - Method for producing synthetic resin foam sheet, coated foam sheet, and decorative foam sheet having a modified surface, and method for producing synthetic resin foam sheet having a modified surface - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: A synthetic resin foam sheet has insufficient flatness on the surface, and thus has insufficient adhesion at the time of printing or lamination. For example, a decorative sheet is laminated using an adhesive. Even so, it is an object of the present invention to improve the problem that peeling occurs at the interface between the foamed sheet and the adhesive layer, and a strong adhesive force that does not lead to the destruction of the bonded material is obtained. SOLUTION: In addition to the conventional corona treatment, the surface of a synthetic resin foam sheet is also roughened, whereby the adhesiveness of the surface can be sufficiently increased, and a decorative sheet or the like is attached. And the adhesive strength was improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed sheet made of synthetic resin whose surface has been modified by improving the adhesiveness of the surface, and a coating utilizing such surface modification. The present invention relates to a method for producing a coated foam sheet in which layers are laminated, a decorative foam sheet in which a decorative sheet is laminated as a coating layer, and a foamed sheet made of synthetic resin having a modified surface.

[0002]

2. Description of the Related Art For typical processing of plastic sheets,
There are printing, and laminating. In printing, adhesion to an ink which is obtained by coloring an adhesive binder resin and diluted with a solvent or the like is important, and in lamination, adhesion to an adhesive becomes a problem. Depending on the synthetic resin that constitutes the plastic sheet, it originally has a free functional group,
Some have good adhesiveness, but some synthetic resins have poor adhesiveness.

[0003] The surface of a synthetic resin sheet or the like is modified to improve its adhesiveness when laminated with another synthetic resin sheet or the like, or to improve the adhesiveness of a printing ink by corona treatment. Various treatments such as (= corona discharge treatment), plasma treatment, flame treatment, and treatment with an acid, alkali, or oxidizing agent are performed.

Of these, corona treatment is often used because it requires only dry operation, requires simple equipment, and enables uniform and high-speed treatment. By corona treatment, the surface of the synthetic resin sheet becomes> C = O or -C
It is said that a functional group generated by oxidation of OOH or the like is generated to improve the adhesiveness. However, even if a corona treatment is applied to the surface of a sheet originally made of a resin having poor adhesion, such as a resin such as polyethylene or polypropylene, the desired improvement in adhesion cannot be obtained.

[0005] In particular, a foamed sheet made of a synthetic resin is insufficient in adhesiveness at the time of printing or laminating. For example, even if a synthetic resin sheet is laminated using an adhesive, the foamed sheet and the adhesive are not used. Peeling occurs at the interface of the layers, and a strong adhesive force that may lead to destruction of the bonded material cannot be obtained.

[0006]

Therefore, in the present invention, a foamed sheet made of a synthetic resin is insufficient in adhesiveness at the time of printing or laminating. For example, a synthetic resin sheet is formed by using an adhesive. It is an object of the present invention to improve the problem that, even when laminating, peeling occurs at the interface between the foamed sheet and the adhesive layer, and at least one of the bonded materials does not have such a strong adhesive force as to cause destruction.

[0007]

In the present invention, the surface of a foamed sheet made of a synthetic resin is modified in addition to the conventional corona treatment, and the surface is roughened so that the adhesiveness of the surface is sufficiently improved. And the above-mentioned problem has been solved.

According to a first aspect of the present invention, at least one of the front side and the back side of a synthetic resin foam sheet is corona-treated and has a rough surface, so that the surface has improved adhesiveness. The present invention relates to a foam sheet whose surface is modified. According to a second aspect of the present invention, at least one surface of the front surface or the back surface of the synthetic resin foam sheet has been subjected to corona treatment, and is a surface having improved adhesiveness due to being a rough surface. The present invention relates to a coated foam sheet having a coating layer laminated thereon. A third invention is characterized in that, in the second invention, the surfaces having the improved adhesiveness are both surfaces of the foam sheet, and a coating layer is laminated on one of the two surfaces. The present invention relates to a coated foam sheet.
A fourth aspect of the present invention is the coated foam according to the second aspect, wherein the surfaces having improved adhesiveness are both surfaces of the foam sheet, and a coating layer is laminated on each of the two surfaces. It is about a sheet. The fifth invention is a second invention.
In any of the fourth inventions, the present invention relates to a coated foam sheet, wherein the coating layer is a decorative sheet. A sixth invention is directed to the coated foam sheet according to any one of the second to fifth inventions, wherein the coating layer is laminated via an adhesive layer. Seventh
The at least one surface of the front surface or the back surface of the synthetic resin foam sheet is a surface that has been subjected to corona treatment and has improved adhesion by being a rough surface, and the one surface has an adhesive. The present invention relates to a decorative foamed sheet characterized in that a decorative sheet is laminated via a layer. The eighth invention provides a method for forming a sheet on a synthetic resin foam sheet,
The present invention relates to a method for producing a foamed sheet made of synthetic resin whose surface has been modified, characterized by performing corona treatment after performing surface roughening treatment. A ninth invention relates to the method for producing a foamed sheet made of a synthetic resin whose surface is modified, wherein the roughening treatment is performed by sandblasting in the eighth invention. The tenth invention is
An eighth invention relates to a method for producing a foamed sheet made of synthetic resin having a modified surface, wherein the surface roughening treatment is performed by a heating embossing method using an embossing plate. According to an eleventh invention, the arithmetic mean roughness of the surface is 150 μm or less on the surface of the synthetic resin foam sheet.
The present invention relates to a method for producing a foamed sheet made of a synthetic resin having a modified surface, wherein a corona treatment is performed at the same time as a corona treatment under a condition of 300 μm to perform a surface roughening treatment.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As a foamed sheet made of a synthetic resin, those made of the following invention resins can be used. That is, polyethylene resin, polypropylene resin, polymethylpentene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl alcohol copolymer Resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate-isophthalate copolymer resin, phenolic resin, polymethyl methacrylate resin, polyethyl methacrylate resin, polybutyl acrylate resin, nylon 6 or nylon 66, etc. Polyamide resin, polyurethane resin, polyisocyanurate resin, cellulose triacetate resin, cellophane, polystyrene resin, polycarbonate resin, polyarylate resin, or polyimide Butter, and the like can be used.

[0010] Among them, polyethylene resin, polypropylene resin, phenol resin, polystyrene resin, polyvinyl chloride resin, polyurethane resin, or polyisocyanurate resin are suitable. In particular, polyethylene resin or polypropylene resin polyolefin resin, This is more preferable because harmful substances are less likely to be emitted during disposal.

As the foaming state of the foamed sheet made of the synthetic resin, two types of open cells and closed cells are known. In principle, either type can be used. , There are some differences. The open-cell foam sheet is composed of interconnected cells, which allows air to move between the cells, resulting in internal condensation and reduced heat insulation performance. Often, other means are needed to prevent the ingress of moisture into the environment. Even if such a measure is taken, there is a possibility that moisture may enter the air bubbles if the measure is damaged.

The closed-cell foam sheet can prevent moisture from penetrating into the cells since each of the cells is sealed, and if used carefully, it can be used alone as a practical heat-insulating sheet. Can be used as Therefore, in the construction field, etc., when using a foam sheet as a heat insulating material, rather than an open-cell foam sheet,
Closed cell foam sheets are preferred.

As the foamed sheet, there are a hard sheet and a soft sheet. Of the foamed sheet made of a thermosetting resin and having closed cells, the foamed sheet made of an epoxy resin, a urea resin, or a phenolic resin is hard, but the thermoplastic resin is a cellulose acetate resin. Is rigid.

[0014] In addition, as a material made of a resin capable of producing both hard and soft foamed sheets, those made hard by adjusting the expansion ratio or the hardness of the resin include polyethylene resin, polypropylene resin, polystyrene resin, and polystyrene. There are foam sheets made of vinyl chloride resin, polyvinyl alcohol resin, polyurethane resin, polyester resin (for example, polyethylene terephthalate resin), polyisocyanurate or silicon resin. However, among these resins, in the case of a foamed sheet made of a polystyrene resin, semi-rigid ones can be manufactured in addition to hard ones.

Among these foamed sheets, soft ones can be manufactured by a method such as melting and extruding a resin composition containing a foaming agent. In addition, a hard material is generally thick and is not easily applied to the present invention as it is, but it is about 2 mm by foaming in a mold having a predetermined gap or by cutting or slicing a thick foam sheet. A sheet having the following predetermined thickness can be obtained.

When comparing a rigid foam sheet and a soft foam sheet, generally, a rigid foam sheet has better heat insulation performance. In particular, the rigid foamed sheet of polyurethane resin is excellent in heat insulation performance since closed cells are filled with fluorocarbon gas or the like having a low thermal conductivity. In addition, since the material of the soft foam sheet is soft, moldability,
It has excellent followability with respect to the shape of the object to be stuck, has high applicability, and has a heat insulation performance close to that of a hard foam sheet.

Other conditions of the foam sheet include thickness, density, and the like. In the case of heat insulation of the wall of a building or a house, it is used with a thickness of several centimeters.However, in the present invention, it is assumed that a sheet-like heat insulating material is attached to provide heat insulation, so that it is too thick. Since application becomes difficult, the thickness of the foamed sheet is preferably about 10 μm to 2 mm.

Other items that describe the foam sheet include density, cell diameter, and thermal conductivity. The density is preferably from 0.01 to 0.1 g / cm ³ , and most preferably from 0.02 to 0.05 g / cm ³ . If the density of the foamed sheet is too low, the bubbles will be continuous with each other and the radiant heat will increase, so that the thermal conductivity will increase, which is not preferable. In the case of closed cells, the smaller the inner diameter of the bubbles is, the better the heat transfer by convection is.
μm is preferred. As the thermal conductivity of the foam sheet,
It is preferably about 0.01 to 0.06 W / mK.

In the corona treatment of the foamed sheet, the foamed sheet is run in contact with a metal roll, and a bar-shaped electrode is placed above the foamed sheet in a width direction of the foamed sheet by several mm from the surface of the foamed sheet. This is performed by maintaining a distance of about 10 to several tens of mm, and applying a high-frequency, high-voltage electric field between the metal roll and the rod-shaped electrode to cause discharge.

In the present invention, in addition to the above-described corona treatment, (1) the surface is roughened by sandblasting or heating embossing before the corona treatment to improve the adhesiveness; ) By changing the above corona treatment conditions and increasing the corona discharge amount per unit area of the foamed sheet, in addition to improving the adhesiveness by the corona treatment which is generally considered, the foamed sheet by corona discharge is improved. The adhesion is also improved by roughening the surface. In addition, it is possible to improve the adhesiveness by performing the surface roughening treatment by sand blasting or heating embossing after the corona treatment. However, in order to produce a sufficient effect, these roughening treatments are performed by the corona treatment. It is preferred to do it before. Hereafter,
When simply saying “processing” or “processing”, it means the processing of the above (1) or (2), or performing such processing.

The sand blasting performed before the corona treatment is performed by using a sand blasting device, and is preferably a ceramic bead made of a ceramic such as alumina, a glass bead, or the like.
A particle having a particle size of about 1 μm to several mm, such as metal particles such as SUS, is used as an abrasive, and a projection speed of the abrasive;
sec to several hundred m / sec, the amount of projection per unit time; sprayed on the surface of the foamed sheet under the condition of several g / min to several hundred kg / min; Surface roughness of about 10, that is, 0.1
A surface roughness of μm to several hundred μm is formed on the surface of the foamed sheet.

The surface roughening treatment by heating embossing performed prior to the corona treatment is performed using a flat or rolled embossing plate having a predetermined uneven shape on the surface, the former being a flat press, and the latter being a flat embossing plate. If necessary, the embossing plate is heated and pressed against the surface of the foamed sheet by a roll press, whereby the surface of the foamed sheet is provided with the unevenness of the surface of the embossed plate.

In order to roughen the surface of the foamed sheet by changing the conditions of the corona treatment, the distance between the foamed sheet and the electrode placed above the foamed sheet is reduced, or the foamed sheet passes between the electrodes. The speed is reduced by reducing the so-called processing speed. Since the change of these conditions differs depending on the corona treatment device, it cannot be said unconditionally,
As an example, under normal processing conditions, the distance between the electrode and the electrode is usually 3 mm and 2.5 mm, and under normal processing conditions the processing speed is 30 m / m and 10 m / m. do it.

The appearance of the foamed sheet does not change between before and after the normal corona treatment. However, by strengthening the corona treatment conditions, the surface of the foamed sheet is roughened and the adhesiveness is reduced. Is improved. If the corona treatment condition is excessively strengthened, a large hole may be formed due to electric discharge. Therefore, in terms of the machining speed, the corona treatment condition is strengthened by 80% or less, preferably 70%, of the machining speed at which the hole is formed by electric discharge. % Or less, so that the arithmetic average roughness of the surface is 150 μm to 30 μm.
It can be 0 μm. In the normal corona treatment, discharge is performed from the upper side perpendicular to the raw material. By discharging the raw material at an incident angle of 10 ° to 80 °, the unit is formed while suppressing the occurrence of holes. The amount of corona discharge per area can be increased.

The foamed sheet of the present invention has at least one surface which is (1) corona-treated, sandblasted before corona-treated or roughened by heating embossing,
Alternatively, (2) by increasing the corona discharge amount per unit area of the foamed sheet by changing the conditions of the above corona treatment, the adhesion of the treated surface is improved as compared with the case of only the normal corona treatment. Therefore, by utilizing this fact, coating with various layers can be performed.

The coating can be performed for various purposes, but typically includes a low moisture permeable sheet or a decorative layer. The coating can be on one side when only one side of the foam sheet is being treated, or on one or both sides when both sides of the foam sheet are being treated. When the low moisture permeable sheet is laminated on one side or both sides, it is possible to suppress the invasion of moisture from the side where the low moisture permeable sheet is laminated. In addition, by laminating the decorative layer, a favorable design feeling can be imparted in addition to the function of the foamed sheet. Therefore, there is an advantage that the decorative layer is applied to a portion that is easily touched by human eyes and does not easily cause discomfort.

As the material of the low moisture permeable sheet, those made of the same plastics as those mentioned as the materials constituting the foamed sheet made of synthetic resin can be used. Generally, uniaxially or biaxially stretched sheets can be used. Things. If necessary, apply a surface treatment such as corona discharge treatment, low temperature plasma treatment, silane coupling agent application, sol-gel agent application, or sand blasting treatment to one or both surfaces of the low moisture permeable sheet, and adhere. You may use what improved the property.

The low moisture permeable sheet is coated with another paint prepared using a resin binder such as polyvinylidene chloride resin having low moisture permeability, or a thin film of metal or metal oxide is formed to reduce gas permeation. It is better to suppress it. In these metal thin films, a mixture of metal oxides having different oxidation numbers such as silicon monoxide and silicon dioxide,
A mixture of a silicon compound and an aluminum oxide may be used, or a mixture of an organic group mainly composed of an inorganic oxide may be used.

As a method of forming a thin film, for example, a vacuum vapor deposition method such as an ion beam method or an electron beam method, a physical vapor deposition method such as a sputtering method, a plasma chemical vapor deposition method, or a thermal chemical vapor deposition method Or a chemical vapor deposition method such as a photochemical vapor deposition method. The thickness of the thin film is
Preferably, it is 50-3000 °, more preferably 100-1000 °. If it is less than 50 °, there is almost no effect of suppressing gas permeation, and if it exceeds 3000 °, cracks may occur in the thin film and gas permeability may be reduced, and the material cost is relatively high. Adhering the aluminum vapor-deposited film to the closed-cell foam sheet also has an effect of preventing the gas having a low thermal conductivity sealed in the closed cells from being replaced with air.

The lamination of the foam sheet and the low moisture permeable sheet is as follows:
An adhesive is applied between the treated surface of the foam sheet and the low moisture permeable sheet or by heat sealing. In addition,
The decorative sheet described later can also be laminated with the foam sheet in a similar manner.

When an adhesive is used, an adhesive selected according to the material constituting the adhesive surface of the foamed sheet, the low moisture permeable sheet, or the decorative sheet as the adherend is used. When an adhesive is used, it is preferable to use a polyurethane resin-based adhesive because the wettability is good and the adhesive strength is high, and lamination can be performed by a dry lamination method.

Another typical coating is the coating of a decorative layer. The foam sheet itself has performance such as heat insulation, sound insulation, or cushioning, but it does not
Alternatively, it is often laminated on the outermost surface of a household electric appliance or the like, and it is desirable that it be subjected to some kind of makeup (or decoration).

As a method of applying makeup, coloring, printing, embossing, wiping painting, or the like on a foam sheet is possible. In this case, a coloring layer is laminated or a printed pattern layer is applied, which corresponds to the concept of coating. It is intended for lamination or further lamination of a printed pattern layer on the lamination of colored layers, and in addition to these, a plastic sheet or the like separate from a foam sheet as a base material, and coloring such a base material , Printing, embossing, or wiping coating or the like, and decorative sheet lamination.

In order to form a colored layer or a printed pattern layer on a base sheet such as a foam sheet or a decorative sheet, a colorant such as a pigment or a dye and a binder resin, a solvent or a diluent are appropriately kneaded. This is performed using an ink composition or a coating composition prepared as described above. As the binder resin, nitrocellulose, cellulose acetate, cellulose butyrate acetate, ethyl cellulose, chloride rubber, cyclized rubber, polyamide resin, polyvinyl chloride resin, vinyl chloride / vinyl acetate copolymer resin, ethylene / vinyl acetate copolymer resin, chlorine Polypropylene, acrylic resin, polyurethane resin or the like can be used.

As a method of forming the colored layer and the printed pattern layer, a known coating method such as roll coating, gravure coating, or spray coating, or a known printing method such as gravure printing, silk screen printing, or offset printing is used. This is done using the method.

The printed pattern layer is formed by printing or the like on a substrate having a releasable surface instead of being formed by direct printing on a foam sheet to form a transfer sheet, and transfer printing using this transfer sheet is performed. May form a pattern layer.

In the above, a colored layer, a printed pattern layer laminated on a foamed sheet, a composite layer in which a printed pattern layer is laminated on the colored layer, or a decorative sheet is provided on the outermost surface with a protective layer made of a transparent resin material. May be laminated. The lamination of the protective layer itself is optional.

The protective layer may be composed of a coating film of a synthetic resin paint, or may be composed of a laminated synthetic resin film in some cases. The protective layer may be covered with a polymethacrylic acid resin film or a fluorine resin film, or may be a resin film such as a fluorine resin which is resistant to contamination.

As the coating film of the synthetic resin paint, a coating material using a thermoplastic resin may be used, but a coating film obtained by curing a thermosetting resin such as a polyurethane resin is excellent in durability, and furthermore, ionizing radiation curing. Of an ionizing radiation-curable resin composition prepared using a hydrophilic polymer or prepolymer, and a coating film obtained by crosslinking and curing by irradiation with ionizing radiation, the protective effect of the lower layer is further improved. .

As the base sheet of the decorative sheet, the plastic sheet mentioned above as a material of the synthetic resin foam sheet can be used, but the base sheet of the decorative sheet has conventionally been made of polyvinyl chloride resin. Sheets are often used and have excellent properties such as workability and flame retardancy. However, if the polyvinyl chloride resin sheet is to be incinerated at the time of disposal, harmful gas may be generated. In that respect, it is preferable to use a polyolefin resin sheet.

The decorative sheet is obtained by forming the above-described colored layer and / or printed pattern layer on the base sheet as described above, and further applying embossing, or embossing and wiping coating as necessary. It becomes.

The method of using the base sheet in the decorative sheet is as follows: (1) When the base sheet is a colored sheet and a printed pattern layer is formed thereon, (2) The base sheet is a transparent sheet and the printed pattern layer is formed on the back surface. In the case of forming a concealing layer further, (3) preparing two base sheets, a colored sheet and a transparent sheet, forming a printed pattern layer on the colored sheet, and laminating a transparent sheet thereon Three cases are typical. In the case of (3), embossing is generally performed when the colored sheet having the printed pattern layer and the transparent sheet are laminated.

The embossing of the decorative sheet is performed by using an embossing roll having desired irregularities formed on the surface and pressing the embossing roll against the surface of the foam sheet while heating the embossing roll as necessary. In cases other than the above (3), it is preferable to form a colored layer or a printed pattern layer on the base sheet and then to perform embossing. After embossing, wiping painting may be performed in which the recesses formed by embossing are filled with an ink-like material. The wiping coating itself can be performed simply by applying an ink-like colorant to the recesses formed by embossing and scraping it off with a squeegee-like material, giving an effect similar to printing, but providing a colorant rather than printing. More depth is obtained because of the large amount of dislocation.

[0044]

EXAMPLES (Example 1 and Comparative Example 1) Soft foam sheet of polypropylene resin (trade name "P-mat" manufactured by JSP Co., Ltd.), thickness: 2.0 mm, expansion ratio: 30
Times), and using a corona discharge treatment device, current value: 5
A, gap with electrode; 2.5 mm, feed speed; 10 m
/ Min condition, a corona discharge treatment was performed to obtain a treated surface having an arithmetic average roughness of 200 µm. A two-part cured urethane adhesive comprising a polyester polyol and an isocyanate compound is applied to the obtained treated surface so that the coating amount when dried is 10 g / m ² , and the solvent is removed by drying. A decorative sheet (two types, an acrylic resin sheet and a laminate of a polyurethane resin layer on the acrylic resin sheet) is attached to the attached surface by a dry lamination method to obtain a decorative foam sheet. (Example 1).

For comparison, the corona discharge treatment was performed at a current value;
5A, gap with electrode; 3 mm, feed rate: 30 m /
The decorative foam sheet was obtained in the same manner as in Example 1 except that the treatment was performed under the conditions of min and the treated surface had a surface roughness of 100 μm (Comparative Example 1).

A 180 ° peel test was performed on the obtained decorative foam sheets of Example 1 and Comparative Example 1. As a result, in the decorative foam sheets obtained in Example 1, the soft foam sheet of polypropylene resin was broken. Until the peeling did not occur between the soft foamed sheet of the polypropylene resin and the above two types of decorative sheets, the peeling occurred in the decorative foamed sheet obtained in Comparative Example 1.

(Example 2 and Comparative Example 2) A flexible foamed sheet made of the same polypropylene resin as used in Example 1 was used.
Using an embossing plate having protrusions of pitch: 500 μm, height: 200 μm, heating embossing was performed under the conditions of surface temperature of the embossing plate: 150 ° C., and the surface shape of the embossing plate was given to the surface of the flexible foam sheet of polypropylene resin. Thereafter, on the same surface, the same corona discharge treatment device as used in Example 1 was used, and the current value was 5 A, the gap between the electrodes was 3 m.
After the corona discharge treatment was performed under the conditions of m and a feeding speed of 30 m / min, the same two types of decorative sheets used in Example 1 were laminated by a dry lamination method in the same manner as in Example 1. A decorative foam sheet was obtained (Example 2).

For comparison, a decorative foamed sheet was obtained in the same manner as in Example 2 except that heating embossing was not performed (Comparative Example 2).

A 180 ° peel test was performed on the obtained decorative foam sheets of Example 2 and Comparative Example 2, and as a result, the soft foam sheet of polypropylene resin was broken in the decorative foam sheets obtained in Example 2. Until the peeling did not occur between the soft foam sheet of the polypropylene resin and the decorative sheet, the peeling occurred in the decorative foam sheet obtained in Comparative Example 2.

Example 3 and Comparative Example 3 The same flexible foamed sheet of polypropylene resin as used in Example 1 was used.
After forming a surface with an arithmetic average roughness of 200 μm by sand blasting using glass beads, on the same surface,
Using the same corona discharge treatment device as used in Example 1,
Current value: 5 A, gap with electrode; 3 mm, feed rate;
After the corona discharge treatment was performed under the condition of 30 m / min, two types of decorative sheets were laminated by a dry lamination method in the same manner as in Example 1 to obtain a decorative foamed sheet (Example 3).

For comparison, a decorative foam sheet was obtained in the same manner as in Example 3 except that sandblasting was not performed (Comparative Example 3).

A 180 ° peel test was performed on the obtained decorative foam sheets of Example 3 and Comparative Example 3, and the soft foam sheet of polypropylene resin was broken in the decorative foam sheets obtained in Example 3. Until the peeling between the soft foamed sheet of the polypropylene resin and the two types of decorative sheets did not occur, the decorative foamed sheet obtained in Comparative Example 3 peeled off both sheets.

[0053]

According to the first aspect of the present invention, it is possible to provide a synthetic resin foam sheet which has been subjected to corona treatment and roughened, and has at least one surface having improved adhesiveness. According to the second aspect of the invention, since the synthetic resin foam sheet is corona-treated and roughened, and the coating layer is laminated on at least one surface, the coating layer is adhered with a strong adhesive force. A coated foam sheet can be provided. According to the invention of claim 3, in addition to the effect of the invention of claim 2, both sides of the synthetic resin foam sheet are corona-treated and roughened, and a coating layer is laminated on one side. Therefore, it is possible to provide a synthetic resin foam sheet in which the coating layer is adhered with a strong adhesive force and the other surface has improved adhesiveness. According to the invention of claim 4, in addition to the effect of the invention of claim 2, both sides of the synthetic resin foam sheet are corona-treated and roughened, and a coating layer is laminated on both sides. Therefore, it is possible to provide a coated foam sheet in which the coating layers on both sides are bonded with a strong adhesive force. According to the invention of claim 5,
In addition to the effects of any one of claims 2 to 4, the present invention can provide a coated foam sheet to which a decorative sheet as a coating layer is adhered with a strong adhesive force. According to the invention of claim 6, in addition to the effects of any of claims 2 to 5, it is possible to provide a coated foam sheet in which the coating layer is more reliably laminated via the adhesive layer. According to the invention of claim 7, at least one side has:
Since at least one surface of the synthetic resin foam sheet is corona-treated and roughened, the adhesiveness is improved, and the decorative sheet is laminated on the surface via an adhesive layer, A decorative foam sheet in which a decorative sheet is more reliably laminated with a strong adhesive force can be provided. According to the invention of claim 8, by performing the corona treatment after the surface roughening, it is possible to impart a high adhesiveness, which cannot be obtained only by performing the corona treatment, to the synthetic resin foam sheet. According to the invention of claim 9, in addition to the effect of the invention of claim 8,
Since the surface is roughened by sandblasting, it is possible to change the degree of surface roughness over a wide range by changing the size of the particles used in sandblasting. Manufacture of synthetic resin foam sheet with modified surface We can provide a method. According to the tenth aspect, in addition to the effect of the eighth aspect, since the surface roughening is performed by the heating embossing method using the embossing plate, the surface roughening can be performed more stably. And a method for producing a synthetic resin foam sheet. According to the invention of claim 11, the corona treatment and the surface roughening treatment are performed only by changing the corona treatment conditions. A method for producing a foamed sheet can be provided.

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Claims (11)

[Claims] 1. A foamed sheet made of a synthetic resin, wherein at least one surface of a front side or a back side is corona-treated,
A foam sheet having a modified surface, characterized by having a rough surface and improved adhesion. 2. A foamed sheet made of synthetic resin, wherein at least one surface of a front surface or a back surface is corona-treated,
A coated foam sheet characterized by having a rough surface and improved adhesiveness, wherein a coating layer is laminated on the one surface. 3. The coated foam according to claim 2, wherein the surfaces having improved adhesiveness are both surfaces of the foam sheet, and a coating layer is laminated on one of the two surfaces. Sheet. 4. The coated foam sheet according to claim 2, wherein the surfaces having improved adhesion are both surfaces of the foam sheet, and a coating layer is laminated on each of the both surfaces. 5. The coated foam sheet according to claim 2, wherein the coating layer is a decorative sheet. 6. The coated foam sheet according to claim 2, wherein the coating layer is laminated via an adhesive layer. 7. A foamed sheet made of a synthetic resin, wherein at least one surface of a front surface or a back surface is corona-treated,
A decorative foamed sheet characterized by having a rough surface and improved adhesiveness, wherein a decorative sheet is laminated on one side of the decorative sheet via an adhesive layer. 8. A method for producing a synthetic resin foam sheet whose surface has been modified, wherein the surface of the synthetic resin foam sheet is subjected to a surface roughening treatment and then a corona treatment. 9. The method according to claim 8, wherein the roughening treatment is performed by sandblasting. 10. The method according to claim 8, wherein the surface roughening is performed by a heating embossing method using an embossing plate. 11. The surface of a synthetic resin foam sheet is corona-treated under the condition that the arithmetic average roughness of the surface is 150 μm to 300 μm, so that the surface is roughened simultaneously with the corona treatment. For producing a synthetic resin foam sheet having a modified surface.