JPH0312115B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a crosslinked polyurethane resin sheet having an adhesive layer on one side.

[Prior art] Lamination in which a cross-linked polyurethane resin sheet is attached to one side of one inorganic glass sheet or one laminated glass (a laminate in which two inorganic glass sheets are laminated with an interlayer interposed between them). Safety glasses are well known and are described in, for example, Japanese Patent Publication No. 59-48775, Japanese Patent Application Laid-open No. 53-27671, and Japanese Patent Application Laid-Open No. 56-104055. The latter two describe the provision of an adhesive layer on one side of a sheet of cross-linked polyurethane resin (called thermosetting polyurethane) that can adhere to the surface of inorganic glass such as thermoplastic polyurethane resin. . When attaching a cross-linked polyurethane resin sheet to one side of a single inorganic glass sheet, a thick adhesive layer with energy absorption properties is required, but if the cross-linked polyurethane resin itself has energy absorption properties, a thin adhesive layer is required. It may also be an adhesive layer.

In other words, cross-linked polyurethane resins generally do not have energy absorbing properties, so if they are attached to a single inorganic glass sheet, they cannot be considered laminated safety glass (in the case of laminated glass, the interlayer has energy absorbing properties). However, certain types of crosslinked polyurethane resin sheets have energy absorbing properties. The role of the crosslinked polyurethane resin sheet is to reduce the risk of injury to the human body from glass fragments when the inorganic glass sheet breaks. However, while general plastic materials are easily damaged by scratches, cross-linked polyurethane resins such as the one mentioned above have a self-healing surface property, and even if scratches occur, they will not disappear. Disappears naturally. On the other hand, such crosslinked polyurethane resins usually do not firmly adhere to the surface of inorganic glass.

[Problems to be solved by the invention] When attaching a crosslinked polyurethane resin sheet having an adhesive layer on one side to an inorganic glass surface,
There is a problem in that air bubbles tend to remain between the surface of the adhesive layer and the surface of the inorganic glass. Normally, a method is adopted in which a cross-linked polyurethane resin sheet is gradually pasted from one end of an inorganic glass sheet to the other while being pressed with a roll to solve the problem of remaining air bubbles (see JP-A-51-66375). ). However, it is not easy to attach it to a bent inorganic glass sheet, and the productivity is not sufficient. In order to solve this problem, the present inventor considered forming fine irregularities called embossing on the surface of the adhesive layer. When a cross-linked polyurethane resin sheet with an embossed adhesive layer is layered on one side of an inorganic glass sheet under reduced pressure, air is removed from the gaps between fine irregularities, and when pressurized in that state to bring them into close contact, air bubbles are left behind. The emboss disappears and the two become one. Generally, a method of forming embossing on the surface of a plastic sheet or film is to form the embossing through an embossing roll. However, it was found that good embossing was not formed even when the adhesive layer-attached crosslinked polyurethane resin sheet was passed through an embossing roll. One cause is that the adhesive has high tack and tends to adhere to the embossing roll. Another reason is that the pressure applied by the embossing roll may cause material displacement in the cross-linked polyurethane resin layer or adhesive layer, causing optical distortion, making it unsuitable for use in laminated safety glass applications. .

[Means for Solving the Problems] As a result of various studies to solve the above problems, the present inventor has developed a method of using a film or sheet with embossing and transferring the embossing onto the surface of the adhesive layer. I found out. The problem of adhesion is solved by using an embossed film or sheet with a peelable (i.e., non-stick) surface; the pressure applied through the film or sheet causes distortion in the adhesive layer. There will be less fear.
This embossed film or sheet having a releasable surface is hereinafter referred to as a protective film or sheet. The present invention relates to a method for producing a cross-linked polyurethane resin sheet having an adhesive layer on one side having an embossed surface which may be temporarily protected with a protective film or sheet. These are the following two inventions.

In a method for manufacturing a cross-linked polyurethane resin sheet containing an adhesive layer for manufacturing transparent laminated safety glass having a layer of cross-linked polyurethane resin sheet on the surface, melt-adhesion is applied to one side of the cross-linked polyurethane resin sheet. A thermoplastic resin adhesive layer is formed on the surface of the adhesive layer, and a protective film or sheet is laminated on the surface of the adhesive layer that is removable and has fine irregularities of 8μ or less in height, and the fine irregularities are covered with an adhesive. Cross-linked adhesive layer having an adhesive layer on the surface which may be temporarily protected with a protective film or sheet, which is characterized by being transferred onto the surface of the layer and peeling off the protective film or sheet if necessary. A method for manufacturing molded polyurethane resin sheets.

In a method for manufacturing a cross-linked polyurethane resin sheet containing an adhesive layer for manufacturing transparent laminated safety glass having a layer of cross-linked polyurethane resin sheet on the surface, a removable and fine layer of 8μ or less in height is applied to the surface. producing a laminate by forming a melt-adhesive thermoplastic resin adhesive layer on the finely uneven surface of a protective film or sheet having unevenness;
The laminate is laminated on one side of a cross-linked polyurethane resin sheet with the surface of the adhesive layer as the lamination surface, and from the time of manufacturing the laminate until the end of laminating the laminate onto the cross-linked polyurethane resin sheet. The surface is temporarily protected with a protective film or sheet, characterized by transferring fine irregularities to the surface of the adhesive layer, and peeling off the protective film or sheet if necessary. A method for producing a crosslinked polyurethane resin sheet having a good adhesive layer.

In the present invention, the protective film or sheet (hereinafter referred to as a protective film) must first have fine irregularities, ie, embossing, on its surface. The embossing may be present only on the surface of the protective film that is in contact with the adhesive layer, or may be present on both surfaces. The height of the embossing is not particularly limited, but it must be 8μ or less,
It is preferably 0.1μ or more, particularly 0.5μ or more. The thickness of the protective film is not particularly limited, but it is preferably thick enough to provide flexibility, particularly preferably about 1 mm or less, more preferably about 0.2 mm or less.
Although there is no particular lower limit, approximately 5 times the height of the embossing is appropriate. The material of the protective film is not particularly limited. Even if the material itself is not releasable, a protective film with a releasable surface obtained by subjecting the surface to releasability treatment can be used, and additives that can impart releasability ( For example, a protective film whose surface is made removable by adding silicone oil or a non-adhesive fluorine compound can be used. The base material of such a protective film may be paper, cloth, metal or plastic. However, a preferable protective film is made of a plastic film whose material itself is removable, or a plastic film whose surface has been treated to be releasable. For example, films made of polyolefins such as polypropylene and polyethylene, fluorine resins, linear polyester resins such as polyethylene terephthalate whose surface has been treated with fluorine compounds or silicone compounds, polyamide resins, styrene copolymer resins, and vinyl chloride resins. Films such as A particularly preferred protective film is a polyolefin film, with a polypropylene film being most preferred.

Preferably, the protective film has antistatic properties. To impart antistatic properties, there are methods such as adding an antistatic agent and forming an antistatic layer on the surface, but the former is preferred. The antistatic agent is usually a surfactant, and antistatic agents that cause less bleeding are particularly preferred. The antistatic protective film prevents dust from adhering not only to the surface of the protective film but also to the surface of the adhesive layer after it is peeled off. In transparent laminates such as laminated safety glass, the presence of dust in the adhesive layer can easily become a very serious problem.

The gist of the first invention is a method of forming an adhesive layer on one side of a cross-linked polyurethane resin, or at the same time as forming the layer, pressing a protective film onto the surface of the layer to transfer the embossment. do.
The second aspect of the present invention is a protective film in which an adhesive layer is formed on one side of the protective film in advance (hereinafter referred to as a laminate).
The gist is a method of manufacturing and laminating this with a crosslinked polyurethane resin sheet. In this case, the transfer of the embossing is carried out between the time of manufacturing the laminate and the end of laminating it with the sheet.

First, the first invention will be explained.

The method of forming an adhesive layer on one side of a crosslinked polyurethane resin sheet is usually to apply a solution or dispersion of the adhesive layer by various methods and dry it.
A method of applying an adhesive raw material and then reacting it to form an adhesive, a method of applying a fluid adhesive itself and solidifying it, etc. are adopted. For example, a method of applying an adhesive solution or dispersion to the surface of the sheet and drying it, a method of applying a reactive raw material mixture capable of forming an adhesive (for example, a reactive raw material mixture capable of forming a thermoplastic polyurethane resin or a blocked isocyanate group), etc. There are two methods: a method of applying a mixture of a linear polyurethane prepolymer with a chain extender and a chain extender) and curing it, and a method of applying a fluid adhesive and curing it while still retaining adhesive properties. As for the application method,
A cast method, ie, a method of casting, is preferred. In some cases, adhesive films or sheets prepared in advance may be laminated. To form a thick adhesive layer, this method or a method of casting a raw material mixture capable of forming a thermoplastic polyurethane resin is suitable. Furthermore, after forming an adhesive layer, a method of forming a crosslinked polyurethane resin sheet on the layer (see Japanese Patent Application Laid-Open No. 162618/1983)
It is also possible to produce a sheet with an adhesive layer.

The embossed protective film is laminated on the adhesive layer surface of the embossed protective sheet on the adhesive layer surface of the crosslinked polyurethane resin sheet on which the adhesive layer is formed. Furthermore, three materials, a crosslinked polyurethane resin sheet, an adhesive film or sheet, and a protective film, may be laminated at the same time.
During this lamination, a certain degree of pressure is usually required in order to transfer the embossment of the protective film onto the surface of the adhesive layer. Depending on the situation, heating may be performed together with pressurization. The pressure means is not particularly limited, but roll pressure is suitable.

Next, the second invention will be explained. In this method, a laminate is first manufactured. The laminate is manufactured by forming an adhesive layer on one side of a protective film, or by laminating a protective film and an adhesive film or sheet. The adhesive layer can be formed by the same methods as described above, namely, applying an adhesive solution or dispersion to one side of the protective film and drying it, applying an adhesive raw material and then reacting it to form an adhesive. This can be done by applying a fluid adhesive and solidifying it. In this case, the adhesive layer formed on the protective film usually has an emboss transferred onto the contact surface of the protective film. On the other hand, in the method of laminating a protective film and an adhesive film or sheet, the emboss may or may not be transferred to the surface of the adhesive layer in the resulting laminate; Depends on the pressure and heating conditions during lamination.
In either case, if the emboss transfer of the manufactured laminate is insufficient, apply pressure or heat to the laminate before laminating the laminate on a cross-linked polyurethane resin sheet to transfer the emboss. You may go. The produced laminate is then laminated onto a crosslinked polyurethane resin sheet with the surface of the adhesive layer serving as the lamination surface. If the adhesive has high adhesive strength at room temperature, this lamination may require little pressure or heating. However, it is usually preferable to apply some degree of pressure or heat. This lamination is preferably performed using a roll, but is not limited thereto. If the embossing has not been transferred or is insufficiently transferred to the surface of the adhesive layer in the laminate, the embossing can also be transferred at the time of lamination.

In the above two aspects of the present invention, after producing the laminate consisting of the crosslinked polyurethane resin sheet, the adhesive layer, and the protective film, the protective film may be immediately peeled off. However, the protective film is usually not removed until just before it is attached to the base material to prevent dust from adhering to it. In some cases, the surface of the crosslinked polyurethane resin can be subjected to secondary processing with the protective film attached. For example, surface-modifying treatments can be impregnated or applied, and the protective film prevents these treatments from reaching the adhesive layer.

As the adhesive, a melt-adhesive transparent thermoplastic resin capable of bonding a crosslinked polyurethane resin and a base material such as an inorganic glass sheet is used. In particular, adhesives that can bond to inorganic glass surfaces include thermoplastic polyurethane resins described in the above-mentioned known examples, as well as melt adhesives such as polyvinyl butyral resins and ethylene-vinyl acetate copolymer resins (EVA). Thermoplastic resins that also have good transparency are preferred. When used for laminated safety glass, it is preferably made of a relatively thick (approximately 0.2 to 1.5 mm) thermoplastic polyurethane resin or polyvinyl butyral resin in order to provide the adhesive layer with energy absorption properties. Otherwise, the thickness of the adhesive layer may be small, in particular about 0.01 to 0.1 mm is employed.
A particularly preferred adhesive layer thickness is about 0.02 to 0.05 mm.

The crosslinked polyurethane resin may be the above-mentioned known examples or other known crosslinked polyurethane resins. These crosslinked polyurethane resins preferably have the above-mentioned self-repairing properties. A particularly preferred crosslinked polyurethane resin is a crosslinked polyurethane resin that has both self-repairing properties and energy absorption properties. Furthermore, for use in laminated safety glass, transparent materials are preferred, and materials that do not yellow are preferred. For this reason, the main raw material polyisocyanate compounds include methylene bis(cyclohexyl isocyanate), isophorodiisocyanate,
Aliphatic or alicyclic polyisocyanate compounds such as hexamethylene diisocyanate are used. The other main raw material is a relatively high molecular weight polyol, and a chain extender may also be used. As the polyol, it is preferable to use a combination of a diol and a trivalent or higher valent polyol. As the chain extender, polyols and polyamines having a molecular weight of about 400 or less, particularly about 200 or less are used. In particular, at least one type of polyester diol and/or polycarbonate diol having a hydroxyl value of approximately 60 to 150 (in the case of two or more types, the above hydroxyl value refers to the average hydroxyl value) and a polyester triol having a hydroxyl value of approximately 150 to 250. (the triol)/(the diol) equivalent ratio of about 0.1 to 0.6 (preferably about 0.15 to
0.35) and preferably has a total average hydroxyl value of about 80 to 140.
About 0.4 to 1.8 equivalents (preferably about 0.7 to 1.5 equivalents) of a substantially divalent chain extender per equivalent of the polyol; Preferred is a crosslinked polyurethane resin obtained by reacting with a polyisocyanate compound. This crosslinked polyurethane resin has self-repairing properties and high energy absorption properties.
Crosslinked polyurethane resins are usually manufactured by a known casting method. In addition, the length of the cross-linked polyurethane resin sheet is not particularly limited, but approximately
0.2 to 20 mm is preferred, particularly about 0.4 to 1.2 mm.

The surface of the crosslinked polyurethane resin sheet may be subjected to surface modification treatment. This surface modification treatment is preferably a treatment that does not impair the self-healing properties of the crosslinked polyurethane resin sheet and improves the surface dirt adhesion and tactility. Specifically, it is appropriate to impregnate the surface of the sheet with an addition polymerizable compound such as an acryloyloxy group or a methacryloyloxy group, and then polymerize it. It is undesirable for a layer consisting only of a polymer of an addition polymerizable compound to form on the surface because this layer does not have self-healing properties.
It is necessary that the crosslinked polyurethane resin be present on the surface that has been surface modified. For example, when measuring the ATR spectrum of a surface that has been surface-modified, the absorption of the crosslinked polyurethane resin is clear, and the absorption of the polymer of the addition polymerizable compound is slight or almost non-existent. is desirable.

The addition polymerizable compound is preferably a polyfunctional compound (having two or more unsaturated groups) such as a polyester of a polyhydric alcohol and acrylic acid or methacrylic acid. Moreover, a monofunctional compound such as an alkyl acrylate may be used in combination with this. The addition polymerizable compound is preferably polymerized by irradiation with energy rays such as ultraviolet rays or electron beams in terms of processing speed. Therefore, it is preferable that the addition polymerization compound is impregnated into the surface of the crosslinked polyurethane resin sheet together with a photopolymerization initiator, a photosensitizer, and the like. Usually, the surface of the sheet is impregnated with a solution containing an addition polymerizable compound, these compounds, and a leveling agent, and then the solvent is removed and the surface is modified by irradiation with energy rays. conduct. As mentioned above, the surface quality treatment can be performed after the laminate is manufactured by the method of the present invention.
Further, it can be applied after surface modification of one side of the crosslinked polyurethane resin sheet. Alternatively, a laminate can be produced by surface-modifying one side of a crosslinked polyurethane resin sheet and then applying the method of the present invention to the non-surface-modified surface. In some cases, a laminate may be produced by subjecting both surfaces of a crosslinked polyurethane resin sheet to a surface modification treatment and then applying the method of the present invention to one surface thereof.

The adhesive layer-attached crosslinked polyurethane resin sheet obtained as described above is used as a material for manufacturing laminated safety glass. As described above, this laminated safety glass is a laminated safety glass having a layer of crosslinked polyurethane resin sheet on its surface. Furthermore, as the base material for this laminated safety glass, not only inorganic glass sheets but also hard transparent plastic sheets such as polycarbonate resin or acrylic resin called organic glass can be used.

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.

Example 1 43.86 parts of poly(1,6-hexane carbonate) diol with a hydroxyl value of about 122 [parts by weight, the same applies hereinafter], poly(caprolactone) with a hydroxyl value of about 90.5
68.93 parts of diol and 12.54 parts of poly(caprolactone) triol having a hydroxyl value of about 195.2 were heated and melted at 100°C, and then mixed with stirring while being dehydrated and degassed under reduced pressure. The temperature of this polyol mixture was lowered to 80°C, and then 6.0×10 ^-3 parts of dibutyltin diurarate [hereinafter referred to as catalyst] and 1,4-butanediol were added.
10.02 parts, and 4,4'-methylenebis(cyclohexyl isocyanate) [hereinafter referred to as H ₁₂ MDI]
64.5 parts were sequentially added and mixed with stirring. An exotherm was observed at the beginning of the reaction. When the system became homogeneous, it was degassed under reduced pressure while stirring at 80°C for 3 minutes. This prepolymerization liquid was cast onto a glass sheet (500 x 500 mm) that had been subjected to mold release treatment, and reacted for 15 hours in a nitrogen purge oven at 120°C to obtain a sheet with a thickness of 0.7 mm that was transparent and had a mirror surface. In addition, the above polyol 3
The average hydroxyl value of people is about 112. The elongation of this crosslinked polyurethane resin sheet was 374%, the breaking strength was 771 kg/cm, and the tearing strength was 30 kg/cm.

A solution of a transparent thermoplastic polyurethane resin adhesive that can firmly adhere to the inorganic glass surface was applied to one side of the sheet at a temperature of about 120°C and under pressure, and dried to form an adhesive layer with a thickness of 0.02 mm. . Furthermore, the adhesive layer is an embossed polypropylene film with antistatic properties (thickness 50μ, emboss height approx. 4μ).
Stack them with the embossed side facing the adhesive layer and apply pressure of about 10
A laminate was produced by applying roll pressure at Kg/cm. When the polypropylene film was peeled off from this laminate, the embossing was successfully transferred to the surface of the adhesive layer.

Example 2 63.07 parts of poly(1,6-hexane carbonate) diol with a hydroxyl value of about 57 99.12 parts of poly(caprolactone) diol with a hydroxyl value of about 90.5 18.02 parts of poly(caprolactone) triol with a hydroxyl value of 195.2 Catalyst 8.25×10 ^{- 3} parts 1,4-butanediol 14.42 parts H ₁₂ MDI 80.37 parts [Average hydroxyl value of polyol 89.25] Using the above raw materials, a transparent crosslinked polyurethane resin sheet with a thickness of 1 mm was made in the same manner as in Example 1. Manufactured. Its physical properties were as follows.

Elongation: 474% Breaking strength: 655 Kg/cm ² Tear strength: 33 Kg/cm An ethanol solution of polyvinyl butyral resin is applied to one side of the above sheet and dried to a thickness of 0.02 mm.
An adhesive layer was formed. The same embossed polypropylene film as in Example 1 was laminated on this adhesive layer to produce a laminate. When the polypropylene film was peeled off from this laminate, the embossing was successfully transferred to the surface of the adhesive layer.

Example 3 The same thermoplastic polyurethane resin adhesive used in Example 1 was applied onto the embossed surface of the same polypropylene film used in Example 1.
Apply MEK/dioxane solution and dry to obtain thickness.
An adhesive layer with a thickness of 0.02 mm was formed. The obtained laminate was then stacked on the same cross-linked polyurethane resin sheet as that produced in Example 1 with the adhesive layer surface as a laminate, and roll pressure was applied at about 30° C. and a linear pressure of 12 kg/cm. When the polypropylene film was peeled off from the obtained laminate, it was found that the embossing was well transferred to the surface of the adhesive layer.

[Effects of the Invention] The present invention has the effect that it is possible to easily form a good embossing on the surface of the adhesive layer of a crosslinked polyurethane resin sheet. In particular, compared to the conventional method using an embossing roll, the method is superior in that it does not cause distortion and does not deteriorate the optical properties of the sheet. Furthermore, when a film having antistatic properties is used, dust and dirt are less likely to adhere to the sheet. These points indicate that the sheet obtained according to the invention is particularly suitable for use in the production of laminated safety glass.

Claims (1)

[Scope of Claims] 1. In a method for producing a cross-linked polyurethane resin sheet containing an adhesive layer for producing transparent laminated safety glass having a layer of a cross-linked polyurethane resin sheet on the surface, A melt-adhesive thermoplastic resin adhesive layer is formed on one side of the sheet, and a protective film or sheet is laminated on the surface of the adhesive layer that is releasable and has fine irregularities of 8μ or less in height on the surface. The surface is temporarily protected with a protective film or sheet, characterized in that the fine irregularities are transferred to the surface of the adhesive layer, and if necessary, the protective film or sheet is then peeled off. A method for producing a crosslinked polyurethane resin sheet having an adhesive layer that may be bonded. 2. The method according to claim 1, wherein the protective film or sheet has antistatic properties. 3 In a method for manufacturing a cross-linked polyurethane resin sheet containing an adhesive layer for manufacturing transparent laminated safety glass having a layer of cross-linked polyurethane resin sheet on the surface, a removable and 8μ high layer on the surface is used.
A laminate is produced by forming a melt-adhesive thermoplastic resin adhesive layer on the finely uneven surface of a protective film or sheet having the following fine unevenness, and then attaching it to one side of a crosslinked polyurethane resin sheet. The laminate is laminated with the surface of the adhesive layer as the lamination surface, and fine irregularities are created on the surface of the adhesive layer between the time of manufacturing the laminate and the end of laminating the laminate onto the crosslinked polyurethane resin sheet. cross-linking having an adhesive layer, the surface of which may be temporarily protected by a protective film or sheet, characterized in that the protective film or sheet is peeled off, if necessary; A method for manufacturing molded polyurethane resin sheets. 4. The method according to claim 3, wherein the protective film or sheet has antistatic properties.