JPH064711B2 - Surface modified cross-linked polyurethane resin sheet - Google Patents

Description

The present invention relates to a self-healing crosslinked polyurethane resin sheet having at least one surface modified on its surface.

Laminated safety glass in which a soft synthetic resin layer is provided on one surface of a hard transparent sheet such as inorganic glass is known as a window material for automobiles. The soft synthetic resin layer has the effect of preventing injury to the human body when the hard transparent sheet is damaged (called tear resistance),
Alternatively, it has an effect of absorbing impact energy when a human body collides. One of the major problems with this type of laminated safety glass is the surface characteristics of the soft synthetic resin layer. The soft synthetic resin layer is liable to be scratched by scratches, is liable to be stained, and is easily attacked by the solvent. In order to prevent the generation of scratches on the surface of the soft synthetic resin layer, it is known to protect the surface of the soft synthetic resin layer with a layer of hard synthetic resin called a so-called hard coat. The hard coat layer generally has good stain resistance and solvent resistance. However, a problem is that the hard coat layer on the soft synthetic resin layer is easily damaged. For example, when the soft synthetic resin surface is pressed, the soft synthetic resin can be deformed to some extent, but the hard coat layer cannot follow the deformation, and the hard coat layer is very easily cracked. As described in Japanese Patent Publication (Kokoku) No. 57-27050), the surface protective layer of the soft synthetic resin layer or the soft synthetic resin layer itself is used in order to solve the fragility of the hard coat layer. It has been proposed to use a soft synthetic resin having specific surface characteristics as. This soft synthetic resin has a property called self-repairing property or self-restoring property. Self-healing property refers to the property that scratches caused by scratches disappear naturally over time, and in particular, it is the same as a specific cross-linked polyurethane-based resin (thermosetting polyurethane-based resin or reticulated polyurethane-based resin). ) Consists of. For a soft synthetic resin having self-repairing property, for example, Japanese Patent Publication No. 55
-6657.

Laminated safety glass in which a soft synthetic resin layer having a surface of a self-healing cross-linking polyurethane resin is provided on one surface of one sheet of inorganic glass or one sheet of laminated glass is known, for example, Japanese Patent Publication No. 57-27050. JP-A-59-48775, JP-A-53-27671 and JP-A-57-176157. The above-mentioned laminated glass means a laminated glass in which two sheets of inorganic glass are laminated with an interlayer film such as polyvinyl butyral resin interposed therebetween. Laminated safety glass requires a soft synthetic resin layer having mechanical properties such as energy absorption and penetration resistance. The above-mentioned known cross-linkable polyurethane resin having self-healing property does not have such mechanical properties. Therefore, in the laminated safety glass using one sheet of inorganic glass, the soft synthetic resin layer is a layer that imparts mechanical properties made of polyvinyl butyral resin or thermoplastic polyurethane resin and has adhesiveness to the surface of the inorganic glass. And two layers of a self-healing crosslinkable polyurethane resin for protecting the layer. In the laminated safety glass using laminated glass, since the interlayer film of laminated glass has mechanical properties, the soft synthetic resin layer can be composed only of the cross-linked polyurethane resin having tear resistance and self-healing property. However, such a cross-linkable polyurethane-based resin often has insufficient adhesiveness to the inorganic glass, and preferably a thin adhesive material layer is provided between the inorganic glass layer and the cross-linkable polyurethane-based resin layer. As the adhesive material, a thermoplastic resin is suitable, and the polyvinyl butyral resin or the thermoplastic polyurethane resin is particularly used. In short, in a laminated safety glass using one sheet of inorganic glass, an adhesive layer thick enough to exhibit mechanical properties is used. In a laminated safety glass using laminated glass, mechanical properties are unnecessary, so a thin adhesive layer is used. ,used.

Although the soft synthetic resin layer having the cross-linked polyurethane-based resin as a surface has excellent surface properties such as self-repairing property, it cannot be said that it fully satisfies all the surface properties required for laminated safety glass. In particular, there is room for improvement in terms of stain resistance. Contamination resistance refers to the property that various stains are difficult to adhere or impregnate on the surface, or the stains that adhere are easy to remove. The present inventor studied the modification of the surface of the cross-linked polyurethane resin having self-repairing property in order to improve the stain resistance of the surface. What is important in this modification is that it should not be a modification that impairs the self-repairing property of the cross-linked polyurethane resin. Therefore, a layer of other material cannot be formed on the surface of the cross-linked polyurethane resin layer. The present inventor, in consideration of this point, as a result of various studies on the improvement of the surface of the cross-linked polyurethane-based resin, by impregnating the surface of the cross-linked polyurethane-based resin with an addition-polymerizable unsaturated compound and curing it. We have found that we can achieve our purpose. Acrylic acid and methacrylic acid are used as the addition-polymerizable unsaturated compound (hereinafter, the term meaning “both” and “meth”).
Acrylic acid ". An ester of “(meth) acrylate” and the like, that is, a (meth) acrylate is used. (Meth) acrylate is known as a part of the hard coat layer forming raw material. However, the formation of the hard coat layer is not preferable as described above, and the self-repairing property of the cross-linked polyurethane resin is lost. What is important in the present invention is that the (meth) acrylate should not be applied to the surface of the cross-linkable polyurethane-based resin in an amount more than that which can be impregnated in the cross-linkable polyurethane-based resin (if excessively applied, the excess of the (meth) acrylate before polymerization is Amount must be removed)
That is, it is necessary that the surface of the crosslinked polyurethane-based resin does not substantially include a polymer layer composed only of a polymer of (meth) acrylate that does not contain the crosslinked polyurethane-based resin component. When the polymer layer is not substantially contained, the layer does not lose the properties of the surface of the cross-linked polyurethane resin even if the layer is formed, and the properties of the polymer layer are not lost. It means that it must be thick enough not to exert its effect,
Its thickness is usually less than 1 μ. In the present invention, surface modification by impregnation curing of (meth) acrylate prevents the surface of the cross-linked polyurethane resin from being impregnated with dirt.
Further, it facilitates removal of stains adhering to the surface of the cross-linked polyurethane resin.

The present invention is the following invention relating to the above surface-modified cross-linked polyurethane resin sheet.

At least one surface of the self-healing cross-linkable polyurethane resin sheet is surface-modified by impregnation curing of at least one unsaturated compound selected from acrylic acid ester and methacrylic acid ester, and the surface is modified. A surface-modified cross-linked polyurethane-based resin sheet with a self-healing surface.

The surface of the cross-linked polyurethane resin is modified by impregnating the surface of the cross-linked polyurethane resin with at least one unsaturated compound selected from acrylic acid esters and methacrylic acid esters and subjecting the unsaturated compound to addition polymerization. Be done. This addition-polymerizable unsaturated compound is hereinafter referred to as a monomer. As the monomer, a compound that is liquid at room temperature is preferable, but a compound that can be dissolved in a solvent can also be used.
The monomer and solvent used must not attack the crosslinked polyurethane resin. The addition polymerization of the monomer may be thermal polymerization, but light such as ultraviolet rays, electron beams, and the like (hereinafter, referred to as energy rays) are preferable. The monomer may be used without being dissolved in a solvent, but is preferably a composition dissolved in a solvent and applied to the surface of the cross-linked polyurethane resin. In addition to the solvent, it is customary to mix and use an addition polymerization initiator such as a photopolymerization initiator or a photosensitizer in the monomer composition. If necessary, a colorant,
You may mix | blend other compounding agents.

As the monomer, not only one kind but also two or more kinds may be used. The monomer may be monofunctional (having one addition-polymerizable unsaturated group) or polyfunctional (having two or more same unsaturated groups). Preferably, a polyfunctional compound is used, or a polyfunctional compound and a monofunctional compound are used in combination. Preferred monomers are (meth) acrylate-based monomers, that is, (meth) acrylic acid esters of mono- or polyalcohols. Examples thereof include polyfunctional (meth) acrylates such as alkyl esters of (meth) acrylic acid, and polyfunctional (meth) acrylates such as (meth) acrylic acid polyesters of polyalcohol. Monofunctional (meth) acrylate having a lower alkyl group (carbon number of 4 or less) such as methyl (meth) acrylate, or ethylene glycol, diethylene glycol or other polyethylene glycol, propylene glycol, dipropylene glycol or other polypropylene glycol, 1 Residues of 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, glycerin, trimethylolpropane, hexanetriol, diglycerin, pentaerythritol, dipentaerythritol, and other polyalcohols with 10 or less carbon atoms Polyfunctional (meth) acrylates selected from polyesters with (meth) acrylic acid are suitable. More preferably,
These monofunctional (meth) acrylates and polyfunctional (meth) acrylates
Acrylate is used together. In order to further improve the stain resistance of the surface, a (meth) acrylate having a polyfluoroalkyl group or a perfluoroalkyl group may be used alone or preferably in combination with the above various (meth) acrylates. In particular (R _f : perfluoroalkyl group having about 3 to 20 carbon atoms, m:
A (meth) acrylate having a group represented by an integer of 1 or more, k: 0 or 1) is suitable.

In addition to the above (meth) acrylate-based monomer, other monomers having a (meth) acrylic acid ester structure can be used. Examples of such a monomer include an acrylic urethane-based monomer (for example, a reaction product of a hydroxyalkyl (meth) acrylate and an isocyanate group-containing compound) and an epoxy acrylate-based monomer (for example, a polyepoxy compound and (meth) acrylic acid). Reaction product). Further, the above-mentioned acrylic acid ester or methacrylic acid ester may be used in combination with other monomers. Examples of the other monomer include allyl-based esters, ethers, carbonates and other allyl-based monomers, styrene-based monomers, and siloxane-based compounds having at least one addition-polymerizable unsaturated group (for example, unsaturated group-containing polydimethylsiloxane). , Other monomers may be used.

As the solvent that can be used in the monomer composition, hydrocarbon-based, halogenated hydrocarbon-based, ester-based, ether-based,
It is possible to use a solvent which does not attack the internally cross-linked polyurethane-based resin such as a ketone-based or other various solvents. As the polymerization initiator, acetophenone, benzophenone, benzyl, benzoin, benzoin ether, other carbonyl compounds, sulfur-containing compounds such as thioxanthone and diphenyldisulfide, azo compounds such as asobisisobutyronitrile, benzoyl peroxide, di- Organic peroxide compounds such as t-butyl peroxide, organic dyes and others may be used. As the sensitizer, for example, an amine compound, a phosphorus compound or the like may be used, and if necessary, a storage stabilizer may be added to the monomer composition.

Apply the monomer or monomer composition to at least one side of the crosslinked polyurethane-based resin sheet by spray coating, dipping, or other means, and after impregnating the monomer, dry and wipe off excess monomer or monomer composition if necessary. Then, the monomer is polymerized by other means. The monomer polymerization is preferably performed by irradiating with energy rays. Polymerization by irradiation of ultraviolet rays is particularly preferable. The impregnated amount of the monomer can be adjusted by the time until the excess is removed after the monomer composition is applied to the surface of the crosslinked polyurethane-based resin, the ratio of the monomer in the monomer composition, and the like. If the amount of the impregnated monomer is too large, the self-repairing property of the surface of the cross-linked polyurethane resin may be deteriorated. Compared to the unmodified surface, the surface-modified surface has a distinctly different touch feeling with a finger, and the sticky feeling is reduced. Further, it is preferable that the ATR spectrum is modified so that, in addition to the absorption of the cross-linked polyurethane-based resin, a slight absorption of the polymer of the monomer is recognized or hardly observed. When a polymer layer of monomer is formed, ATR
It is observed that Spectryl absorbs most of the polymer and that the layer is easily damaged by pressing. It is not preferable that the self-repairing property is reduced by 50 g or more as measured by the measuring method described below due to surface modification. Usually, it is preferable to maintain the degree of decrease within about 20 g, particularly within about 10 g.

The material of the cross-linkable polyurethane resin sheet in the present invention needs to be a cross-linkable polyurethane resin having self-repairing property. The crosslinkable polyurethane resin having self-repairing property is known as described above, and this known crosslinkable polyurethane resin can be used in the present invention.
However, more preferably, a cross-linked polyurethane resin having high mechanical properties and self-repairing property is used. The use of such a cross-linked polyurethane-based resin is excellent in that it is not necessary to use a thick adhesive material having high mechanical properties such as polyvinyl butyral-based resin or thermoplastic polyurethane-based resin when applied to the laminated safety glass. It has different characteristics. The cross-linked polyurethane resin having such characteristics will be described in detail below.

The polyurethane resin is obtained by reacting a polyvalent active hydrogen-containing compound, particularly a polyol, with a polyvalent isocyanate group-containing compound (hereinafter referred to as a polyisocyanate compound). When both of these two compounds are divalent, the thermoplastic polyurethane resin is obtained, and when at least one of the two compounds is more than divalent, a crosslinkable polyurethane resin is obtained. The physical properties of the crosslinkable polyurethane-based resin are mainly affected by the type of active hydrogen-containing compound.
Generally, a polyurethane resin elastomer having high mechanical properties is obtained by using a high molecular weight active hydrogen-containing compound in combination with a low molecular weight active hydrogen containing compound called a chain extender or a crosslinking agent. However, according to the study by the present inventor, it was found that the self-repairing property and high mechanical properties of the crosslinked polyurethane-based resin tend to contradict each other. That is, the cross-linked polyurethane resin having high mechanical properties has low self-healing property. Therefore, the cross-linking polyurethane-based resin having both of these properties is a relatively limited type of cross-linking polyurethane-based resin. Therefore, such a cross-linkable polyurethane-based resin must basically be a cross-linkable polyurethane-based resin obtained by using the following raw materials.

1. A relatively high molecular weight polyol (A) and a low molecular weight active hydrogen-containing compound (hereinafter referred to as a chain extender) (B) must be used in combination. If the chain extender (B) is not used in combination, a crosslinked polyurethane resin having high mechanical properties cannot be obtained.

2. In the above polyol (A), it is necessary to use a diol and a polyol having a valency of 3 or more, and their average hydroxyl value is about
The equivalent ratio of 70 to 150, (polyhydric polyol having a valency of 3 or more) / (diol) should be in the range of about 0.1 to 0.6. If the average hydroxyl value and the equivalent ratio of both polyols are higher than this, the mechanical properties will decrease, and if it is lower than this, the self-repairing property will decrease.

3. The chain extender (B) should be a substantially divalent compound having a functionality of about 2.1 or less, and the polyisocyanate compound should also be about 2.1.
It must be a substantially divalent polyisocyanate compound that is functional or less. If the number of functional groups is higher than this, the mechanical properties will deteriorate.

4. It should be about 0.4 to 1.8 equivalents of chain extender (B) to polyol (A) 1. If it is higher than this, the self-repairing property is lowered, and if it is lower than this, the mechanical properties are lowered.

In addition, as a natural premise of the production of the cross-linked polyurethane resin, the total equivalent amount of the polyol (A) and the chain extender (B) is almost equal to the equivalent amount of the polyisocyanate (C) compound.
The latter, about 0.8 to 1.2 equivalents, is suitable for the equivalent amount. Further, the polyisocyanate compound (C) needs to be a non-yellowing polyisocyanate compound, and an alicyclic or aliphatic polyisocyanate is used. The hydroxyl value is used as a numerical value related to the molecular weight of the polyol. When using a diol and a polyol having a valency of 3 or more,
This is because the effect of the molecular weight on the physical properties cannot be expressed simply by the average value of those molecular weights. The relationship between the hydroxyl value and the molecular weight is represented by the following formula.

[OHV] = ([a] / [MW]) × 56.1 × 10 ³ [OHV]: Hydroxyl value (mgKOH / g) [a]: Number of functional groups [MW]: Molecular weight The above polyol (A) has a hydroxyl value of about 40. ~ 250, especially about 60-15
0 diol and hydroxyl value of about 50-300, especially about 100-250 3
It is preferably composed of a combination of polyols having a valency or higher. The diol and the polyol having a valence of 3 or more may each be composed of a combination of two or more kinds. In that case,
Each polyol may be in the above range as long as the average hydroxyl value is in the above range. However, the upper limit of the hydroxyl value of each polyol does not exceed about 400 in order to distinguish it from the chain extender (B) described later. A preferred diol is a combination of a diol having a hydroxyl value of about 90 to 100 and exceeding the upper limit thereof and a diol having a hydroxyl value of the upper limit or less, or a diol having a hydroxyl value of less than the lower limit and a diol having the lower limit or more. The most preferred polyol (A) is a combination of at least two diols having an average hydroxyl value of about 60 to 130 and at least one trihydric or higher polyol having an average hydroxyl value of about 150 to 250, particularly triol. Further, the average hydroxyl value in the combination of the diol and the polyol having 3 or more valences is most preferably about 80 to 140, and the equivalent ratio thereof is most preferably about 0.15 to 0.35. Chain extender
(B) is composed of at least one kind of diol or diamine having a molecular weight of about 280 or less, and diol having a molecular weight of about 160 or less is particularly preferable. A trivalent or higher valent low molecular weight active hydrogen-containing compound such as a low molecular weight triol may be used in an extremely small amount,
It usually consists of divalent compounds only. Most preferably, the amount of chain extender per equivalent of the above polyol is about 0.7 to 1.3 equivalents. When the chain extender (B) is a low molecular weight polyol, the average hydroxyl value of the diol in the polyol (A), the polyol having a valence of 3 or more, and the low molecular weight polyol is not particularly limited. Although not limited, about 120 to 250, particularly about 150 to 220, shows the best performance in terms of both mechanical properties and self-healing property, and is most preferable as a raw material for the crosslinkable polyurethane resin in the present invention.

As the above-mentioned relatively high molecular weight diol and trivalent or higher valent polyol, polyester-based polyols, polycarbonate-based polyols, and poly (oxytetramethylene) -based polyols are selected as the main polyols (that is, as a majority of all polyols). The use of polyoxybropyrene-based polyol cannot be used in a large amount in view of the mechanical properties of the cross-linked polyurethane-based resin. Particularly preferred polyols are polyester-based polyols and polycarbonate-based polyols. However, the use of only the polyester polyol tends to cause a difficulty in the water resistance of the cross-linked polyurethane resin. On the other hand, a polycarbonate-based polyol has a high viscosity and may cause a problem when it is formed into a sheet by cast molding. Therefore, both are most preferably used in combination. However, although there are few kinds of commercially available polycarbonate-based polyols, there are problems as described above, but it is considered that it is possible to use only the polycarbonate-based polyol if an appropriate one having a low viscosity is available. Currently, the ratio of polycarbonate-based polyols to all polyols is at least about 15
Preference is given to using weight percent, especially about 25 weight percent. At present, there is no commercial product of a trivalent or higher-polycarbonate-based polyol, but of course, it can be used if it is available. Therefore, at the present time, due to the problem of viscosity and the problem of availability of polycarbonate-based polyols, the cross-linkable polyurethane-based resin is the best combination of three polyols of trihydric or higher polyol, polycarbonate-based diol, and polyester-based diol. Bring However, the combination is not limited to this as long as such a restriction is eliminated. The presently preferred polycarbonate-based diol has a hydroxyl value of about 40 to 200, and its ratio to the total diol is about 25 to 75% by weight, particularly about 25 to 60% by weight.

Polycarbonate polyols include ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, neopentyl glycol, 1,
Polycarbonate diol obtained by using 6-hexanediol, cyclohexanedimethanol, and other aliphatic or alicyclic divalent or higher alcohols, and more than divalent obtained by using a small amount of trivalent or higher alcohols in combination Polycarbonate polyols may be used. Further, a polycarbonate-based polyol obtained by ring-opening polymerization of a cyclic carbonate compound may be used. It is known to apply a polyurethane resin using a polycarbonate polyol to a laminated safety glass, for example, Japanese Patent Publication No. Sho 55-19249, Japanese Patent Publication No. Sho 49-98818, and Japanese Patent Publication No. Sho 51-918.
-144492, JP-A-59-22197, etc. In the present invention, polycarbonate-based polyols as described in these known examples can be used. The most preferred polycarbonate-based polyols are poly (1,6-hexanecarbonate) diol and poly (1,6-hexane / 1,4-dimethylenecyclohexanecarbonate) diol.

As the polyester polyol, a polyester polyol having a polyhydric alcohol residue and a polycarboxylic acid residue or a polyester polyol having a hydroxycarboxylic acid residue is suitable. The former is preferably a polyester polyol having a dihydric alcohol residue, or both of it and a small amount of a residue of a trihydric or higher alcohol, and a dibasic acid residue. For example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, glycerin,
Polyester polyols having residues such as trimethylolpropane and hexanetriol and residues such as adipic acid, azelaic acid, sebacic acid and phthalic acid are suitable. The latter is preferably a polyester-based polyol obtained by adding a cyclic ester such as ε-caprolactone (hereinafter referred to as caprolactone) or γ-butyrolactone or hydroxycaproic acid to the above polyhydric alcohol, water or other polyvalent compounds. In addition, the above-mentioned known examples, particularly the polyester polyols described in JP-A-53-27671 and JP-A-57-176157 can be used. Furthermore, as a general description, "Plastic Materials Course [2] Polyurethane Resin" published by Nikkan Kogyo Shimbun
Mention may be made of polyester-type polyols of the kind described on pages 56 to 61 and pages 133 to 168. The most preferable polyester-based polyols are poly (1,4-butylene adipate) -based polyols, poly (ethylene adipate) -based polyols, poly (1,4-butylene azelate) -based polyols, and poly (caprolactone) -based polyols. Poly (caprolactone) -based polyols are particularly preferred as trihydric or higher valent polyols, especially triols. In addition to the above-mentioned polycarbonate-based polyol and polyester-based polyol, poly (oxytetramethylene) -based polyol can be used as a main polyol.
This polyol is often inferior to the former two in terms of mechanical properties and weather resistance, but since the water resistance is superior to that of the polyester-based polyol, it is particularly preferable that a part of the polyester-based polyol is
You can substitute for everything. However, even if it is usually used, it is preferably not used as a main polyol. Other polyols other than these (for example, polyoxypropylene-based polyols and polybutadiene-based polyols are not normally used, but it is preferable that they are not used as the main polyol even if they are used for some purpose. Of course, mechanical properties, If there is a polyol excellent in terms of weather resistance, water resistance, viscosity, etc., its use will not be hindered.

The chain extender (B) is preferably a diol as described above, and examples thereof include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol and 1,6. -Hexanediol, cyclohexanedimethanol and the like may be used. Instead of or together with these, a dihydroxycarboxylic acid or diamine such as dimethylolacetic acid, dimethylolpropionic acid, diaminodicyclohexylmethane or isophoronediamine can be used. A preferable chain extender is an aliphatic diol having 2 to 6 carbon atoms, and 1,4-butanediol and ethylene glycol are particularly preferable.

As the polyisocyanate compound (C), as described above, 2
A non-yellowing modified diisocyanate is used. Specifically, for example, methylene-bis (cyclohexyl isocyanate), isophorodiisocyanate, cyclohexane diisocyanate, tetramethylene diisocyanate,
There are hexamethylene diisocyanate and divalent modified products thereof (for example, prepolymer modified product and urea modified product). Preferred polyisocyanate compound is
4,4'-methylene-bis (cyclohexyl isocyanate) and isophorodiisocyanate, of which the former is particularly preferable. Although a small amount of trivalent or more non-yellowing polyisocyanate can be used in combination, usually only divalent polyisocyanate compounds are used.

In addition to the main raw materials, the above-mentioned or other cross-linkable polyurethane-based resins often require small amounts of other auxiliary raw materials. In particular, catalysts and stabilizers are often essential raw materials. As the catalyst, an organometallic compound catalyst such as an organotin compound is suitable. As the stabilizer, it is preferable to use one kind or two or more kinds of antioxidants, ultraviolet absorbers, light stabilizers and the like. For example, a hindered phenol-based compound, a hindered amine-based compound, a phosphoric acid ester-based compound, a benzophenone-based compound, a benzotriazole-based compound, or the like can be used. In addition, a small amount of a colorant, a flame retardant, a release agent, an adhesion improver, etc. may be used depending on the purpose. In some cases, small amounts of diluents such as solvents may be used, but are usually unnecessary. The crosslinkable polyurethane-based resin is produced using the above raw materials by a method such as a one-shot method, a prepolymer method or a quasi-prepolymer method. The sheet is formed by the cast method. Particularly preferred is a method in which the raw materials are mixed by a one-shot method, the mixture is cast on a smooth surface, and solidified to form a sheet. In addition to the above-mentioned known examples, sheet formation by the casting method is also disclosed in JP-A-55-105534 and JP-A-56-1626.
No. 18 publication. When cast molding is performed on the surface of a flexible substrate such as a polyethylene terephthalate resin film, a laminate of the flexible substrate and the crosslinked polyurethane-based resin sheet is obtained. This laminate can be used as it is for surface modification by impregnation curing of the above-mentioned monomer. That is, since one surface of the laminated body is the surface of the cross-linked polyurethane resin sheet, one surface is surface-modified by performing surface modification on this surface. The flexible substrate protects the other surface, and even if the laminate is dipped in the monomer solution, the other surface is not impregnated with the monomer. In this case, the flexible substrate is peeled off after the surface modification. Of course, without using a flexible substrate, the surface of the cross-linked polyurethane-based resin formed on the substrate by cast molding can be surface-modified by applying a monomer subsequent to cast molding. The surface modification is not limited to these methods, of course, and can be performed using a crosslinked polyurethane-based resin sheet separated from the substrate.

The cross-linked polyurethane resin obtained by using the above raw materials has high mechanical properties. For example, its elongation (elongation at break) is about 250% or more, and its breaking strength is about 300 kg / cm ²
That is all. For example, in the cross-linked polyurethane resin shown in the examples below, the elongation of about 300-600% about 500-800
It has a breaking strength of kg / cm ² . Moreover, the relationship between elongation and tensile strength up to fracture (relationship represented by stress-strain curve)
Shows a completely different behavior between the above-mentioned cross-linked polyurethane-based resin and a known cross-linked polyurethane-based resin. That is, it can be seen that the crosslinked polyurethane-based resin behaves similarly to the thermoplastic polyurethane-based resin having excellent mechanical properties, and has excellent mechanical physical properties. On the other hand, Japanese Patent Publication Sho 59
The known cross-linked polyurethane-based resin described in JP-A-488775 has an elongation of about 100% and a breaking strength of about 240 kg / cm ² (value converted in units), and it cannot be said that mechanical properties are sufficient.

Note that, usually, the surface modification lowers the elongation and mechanical properties of the cross-linked polyurethane resin to some extent. The extent of the decrease depends mainly on the amount of the impregnated monomer, but it is considered that it depends on the polyfunctionality of the monomer.

The thickness of the surface-modified cross-linked polyurethane resin sheet of the present invention is not particularly limited. However, as a material for laminated safety glass, its thickness is about 0.2-2 mm, especially about
0.4 to 1.5 mm is preferable. Further, this sheet is preferably a colored or non-colored transparent sheet. However, when it is used for purposes other than the material for laminated safety glass, it does not necessarily have to be transparent. The cross-linked polyurethane-based resin obtained by using the above raw materials is usually extremely transparent. Furthermore, it is preferable that the sheet of the present invention has a smooth surface. Inferior surface smoothness causes optical distortion and is not suitable as a material for laminated safety glass. In the cast molding, if the surface of the substrate on which the raw material is cast is smooth, a smooth sheet can be obtained. By using a substrate having an extremely smooth surface as the substrate, a sheet having higher smoothness can be obtained as compared with the extruded thermoplastic resin sheet. The reason why the cast molding is preferable as the sheet forming method is that this extremely smooth surface can be obtained. Of course, when the sheet of the present invention is used for applications other than the material for laminated safety glass, the surface smoothness is not always an essential requirement. For example, a substrate having a matte surface or an embossed surface can be used to obtain a crosslinked polyurethane-based resin sheet having a surface to which the surface is transferred. The surface-modified crosslinked polyurethane-based resin sheet of the present invention is most suitable as a material for laminated safety glass. Hereinafter, application to this laminated safety glass will be described.

The laminated safety glass obtained by using the sheet of the present invention is a transparent hard sheet consisting of one sheet of inorganic glass or one sheet of laminated glass, and at least the surface of which is a cross-linked polyurethane resin sheet modified. Most preferably, laminated safety glass is one surface composed of one layer or a soft synthetic resin layer having a multi-layered structure, which is a different surface, is the surface of the inorganic glass, and the other surface is the surface of the modified cross-linked polyurethane resin. However, the present invention is not limited to this. One sheet of organic glass, laminated sheet using laminated glass or other inorganic or organic glass, laminated body of inorganic glass and organic glass, inorganic or organic lens, The sheet of the present invention can be applied as a material for laminated safety glass or other transparent laminated body in which one side or both sides of another transparent hard material is protected by a soft synthetic resin layer. Polycarbonate resin and acrylic resin are suitable as the organic glass material. The soft synthetic resin layer may be composed only of the layer of the surface-modified cross-linked polyurethane resin sheet having self-healing property of the present invention. However, in laminated safety glass using inorganic glass, an adhesive layer made of an adhesive material is interposed between the surface of the inorganic glass and the crosslinked polyurethane-based resin sheet layer. This adhesive layer may be a thin layer or a thick layer that can exhibit mechanical properties. As the material, a synthetic resin having a thermoplastic property such as polyvinyl butyral resin, thermoplastic polyurethane resin, EVA resin is preferable. EVA-based resin refers to a synthetic resin composed of a copolymer of monomers containing ethylene and vinyl acetate as main components or a partial hydrolyzate thereof.

The material of the cross-linking polyurethane resin sheet having self-repairing property may be the cross-linking polyurethane resin described in the above-mentioned known examples. For example, a polyethertriol having a molecular weight of about 450 (a hydroxyl value of about 374), which is a propylene oxide adduct of trimethylolpropane, and a polyisocyanate compound having a valence of 3 or more, which is a burette of 1.6-hexanediisocyanate, are reacted in substantially equivalent amounts. There is a cross-linked polyurethane resin obtained. However, more preferably, the cross-linking polyurethane resin described in detail above, which has both self-repairing properties and high mechanical properties, is suitable. Such a cross-linked polyurethane-based resin sheet is particularly advantageous as a material for laminated safety glass using one sheet of inorganic glass. That is, a laminated safety glass can be constructed by providing a cross-linked polyurethane-based resin sheet layer on one surface of one sheet of inorganic glass via a thin adhesive layer, and using a thick adhesive layer for imparting mechanical properties. It is possible to avoid various problems associated with. For example, it is not easy to manufacture a sheet of a thick adhesive material having excellent optical properties, and lamination of this sheet and a sheet of a cross-linkable polyurethane resin is complicated. On the other hand, it is easy to form a thin adhesive layer on one side of the crosslinked polyurethane-based resin sheet, and for example, a solution of the adhesive material is applied to easily produce the crosslinked polyurethane-based resin sheet with the adhesive layer. You can. The adhesive layer is not necessarily required when the surface of the transparent hard material on the side of the cross-linked polyurethane resin layer is not the surface of the inorganic glass.

Laminated safety glass is produced by laminating a sheet of cross-linked polyurethane resin having an adhesive layer on one side and surface-modified on the other side with a transparent hard material, especially one inorganic glass sheet or laminated glass. Preferably. However, transparent hard materials, adhesive sheets or films,
And a method of laminating three of the cross-linked polyurethane resin sheet at the same time, forming an adhesive layer on one surface of the transparent hard material,
A method of laminating a cross-linked polyurethane-based resin sheet thereon may also be used. However, in laminated safety glass used as a window material for automobiles, a bent inorganic glass sheet or a laminated glass sheet is often used, and in this case, the first method is most suitable. Hereinafter, a sheet of a cross-linked polyurethane resin having an adhesive layer on one side and surface-modified on the other side is referred to as a pre-laminated sheet.

The surface of the preformed sheet is surface-modified on one side (may be on both sides in some cases). It is manufactured by forming an adhesive layer made of an adhesive material on one surface). For example, an adhesive layer may be applied by applying an adhesive or its raw material mixture to the surface of the surface-crosslinked polyurethane-based resin sheet, applying a solution or dispersion of an adhesive to remove the medium, or using an adhesive sheet or a sticking method. Is formed. When a thermoplastic polyurethane-based resin or the like is used as the adhesive, the raw material mixture can be applied to the surface of the cross-linked polyurethane-based resin sheet to form the thermoplastic polyurethane-based resin on the surface. The surface on which the adhesive layer is not formed can be covered with a peelable material such as a synthetic resin film in advance to protect the surface from adhesion of the adhesive. The surface on which the adhesive layer is formed is preferably not surface-modified. This is because the surface-modified surface may have reduced adhesiveness.

The method of laminating with the transparent hard material using the above preliminary laminated sheet is not particularly limited. For example, a transparent hard material and a preliminary laminated sheet are laminated without using a method of removing the mold material after heating and pressurizing the preliminary laminated sheet by sandwiching the preliminary laminated sheet between the mold material having a releasable surface and the transparent hard material. A method (see, for example, Japanese Patent Publication No. 58-12140) can be used. In some cases, it is possible to use a method in which the transparent hard material and the preliminary laminated sheet are stacked and heated while being pressurized with a roll or the like. Before laminating, the laminating surface of the transparent hard material may be subjected to an adhesion improving treatment as described in the above-mentioned known example. For example, in the case of inorganic glass, it is preferable to previously treat the laminated surface with an organosilicon compound, for example, an alkoxysilane containing an amino group or a glycidoxy group.
It is also preferable to pre-emboss the adhesive layer surface of the preliminary laminated sheet in advance in order to prevent air or the like from remaining as bubbles on the laminated surface during lamination. The embossing treatment means providing fine irregularities. By this embossing process, a fine flow passage is formed between both laminated surfaces at the time of stacking, air and the like are eliminated, and the flow passage is gradually closed, so that the possibility of bubbles remaining is reduced. The degree of unevenness is usually several microns or less.

In the laminated safety glass, the transparent hard material is preferably a sheet having a substantially constant thickness or a bent sheet. The thickness is not particularly limited, but it is suitable to be about 0.2 mm or more, particularly about 2 to 20 mm.
If it consists of one sheet of inorganic glass, it is preferably about 2-6 mm. When it is made of laminated glass, it is preferably about 4 to 10 mm. Among the soft synthetic resin layers, the surface-modified crosslinked polyurethane-based resin sheet layer has a thickness of at least about 0.2 mm, particularly preferably about 0.4 mm. In a laminated safety glass in which a cross-linked polyurethane-based resin layer having particularly high mechanical properties is laminated with one sheet of inorganic glass, the thickness of the layer is about
It is preferably 0.5 to 1.5 mm. In this case, a thickness of the adhesive layer of less than about 0.2 mm, especially about 0.1 mm or less is sufficient, and usually about 0.05 mm or less, particularly 0.01 to 0.03 mm is adopted. The thickness of the adhesive layer in this range is also suitable when laminated glass or organic glass is used as a transparent hard material. When the adhesive layer is required to have high mechanical properties, for example, when one sheet of inorganic glass is combined with a cross-linking polyurethane resin having no high mechanical properties, the adhesive layer has a thickness of about 0.2 mm or more, particularly about 0.4 to 1.5 mm. A thick adhesive layer is adopted. The thickness of the laminated safety glass as a whole is not limited to a certain thickness when the application is different, but it is usually about 15 mm or less, particularly about 3 to 8 mm as a window material for automobiles.

The present invention will be described below with reference to examples and the like, but the present invention is not limited to these examples. The physical properties were measured by the following methods.

[Physical property measurement method] Self-healing property: Scratch the surface-modified surface of the cross-linked polyurethane resin with a loaded diamond tip of 10 μmφ, and express it as the maximum load at which scratches that occur within 10 minutes at 25 ° C. can disappear. The scratches were visually removed. In the case of an inorganic glass having no self-healing property, a scratch was caused by a load of about 5 g by this method.

Elongation, breaking strength, tensile strength: According to JIS K 6301.

Light transmittance, Taber abrasion: According to JIS K 6301.

Contamination resistance: The degree of mark removal when a cross-linked polyurethane resin surface-modified surface is marked with a felt pen and wiped with ethanol 24 hours later.

Feeling: Feeling when rubbing the surface-modified surface of the cross-linked polyurethane resin with a finger. Good means that the sliding is good.

Example 1 [Production of cross-linked polyurethane-based resin sheet] 43.86 parts of poly (1,6-hexanecarbonate) diol having a hydroxyl value of about 122 [parts by weight, the same applies hereinafter], hydroxyl value of about 90.5
68.93 parts of a poly (caprolactone) diol of, and a poly (caprolactone) triol having a hydroxyl value of about 195.2 12.
After 54 parts were heated and melted at 100 ° C., they were stirred and mixed while dehydrating and deaerating under reduced pressure. After lowering the temperature of this polyol mixture to 80 ° C, dibutyltin dilaurate [hereinafter referred to as catalyst]
6.0 × 10 ^-3 parts, 1,4-butanediol 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 with the start of the reaction. When the system became uniform, degassing under reduced pressure was performed while stirring at 80 ° C. for 3 minutes. The glass sheet (50
(0 × 500 mm) and cast for 15 hours in a nitrogen purge furnace at 120 ° C. to obtain a 0.7 mm-thick transparent and mirror-finished sheet. The average hydroxyl value of the above three polyols is about
112. The cross-linked polyurethane resin sheet had an elongation of 347%, a breaking strength of 771 kg / cm and a tear strength of 30 kg / cm.

Hereinafter this sheet is referred to as A-1.

[Surface Modification] After protecting the cross section of the urethane sheet A-1 with a peelable film, the laminate is placed in the following solution (a) or (b).
Immersion was carried out at a rate of 10 cm / min, and immediately the rate of pulling was 10 cm / min. After drying in an oven at 60 ° C. for 1 minute, UV irradiation was carried out from a distance of 10 cm under a N ₂ stream at a conveyor speed of 5 mm / minute using a 120 cm / cm conveyor type high-pressure mercury irradiator for surface modification. After completion of the surface modification, the peelable film was removed and the surface performance was tested. The results are shown in Table 1 below. In the table, Example 1-a shows the surface modified by using the solution (ii), and Example 1-b shows the surface modified by using the solution (ii).

Solution (a) 1,6-hexanediol diacrylate 1200 parts Benzophenone 60 parts Acetone 1800 parts Leveling agent 15 parts Solution (b) Neopentyl glycol diacrylate 1200 parts Benzophenone 60 parts Acetonitrile 1800 parts Antifoaming agent 15 parts Example 2 8 Crosslinked polyurethane resin sheet A-
2 to A-8 were produced. The same solution as in Example 1 for each sheet (a)
Using (b) and (b), surface modification was performed in the same manner as in Example 1. The surface performance of the obtained surface modified sheet is shown in Table 1 below. In Example n-i, the sheet A-n was used as a solution.
The sheet treated with (a), Example n-b shows the sheet A-n treated with the solution (b).

In addition, the surface performance of the sheet An before surface modification was compared with Comparative Example A.
It is shown in Table 1 as -n. A-2 Poly (1,6-hexanecarbonate) diol with a hydroxyl value of about 57.63 parts Poly (caprolactone) diol with a hydroxyl value of about 90.5 99.12 parts Poly (caprolactone) triol with a hydroxyl value of about 195.2 18.02 parts Catalyst 8.25 × 10 ^-3 Part 1,4-butanediol 14.42 parts H ₁₂ MDI 80.37 parts average hydroxyl value of polyol 89.25 sheet thickness 1.0 mm elongation 474% breaking strength 655 kg / cm ² tear strength 33 kg / cm A-3 poly (hydroxyl value about 54.52 1,6-hexane carbonate) diol 43.53 parts Poly (caprolactone) diol with a hydroxyl value of about 70.79 68.41 parts Poly (caprolactone) triol with a hydroxyl value of about 195.2 12.44 parts Catalyst 6.0 × 10 ^-3 parts 1,4-butanediol 12.42 parts H ₁₂ MDI 63.18 parts Polyol average hydroxyl value 88.5 Sheet thickness 0.7mm Elongation 415% Breaking strength 655kg / cm ² Tear strength 38kg / cm A-4 Poly (1,6-hexanecarbonate) diol with hydroxyl value 54.52 35.68 parts Acid group value of about 90.79 poly (caprolactone) diol 124.87 parts hydroxyl number of about 195.2 poly (caprolactone) triol 17.84 parts catalyst 8.25 × 10 ^-3 parts of 1,4-butanediol 14.27 parts H ₁₂ MDI 82.34 parts average hydroxyl value of the polyol 94.0 Sheet thickness 1.1mm Elongation 495% Breaking strength 690kg / cm ² Tear strength 35kg / cm A-5 Poly (1,6-hexanecarbonate) diol with hydroxyl value about 53.3 44.54 parts Poly (caprolactone) with hydroxyl value about 91.1 Diol 69.99 parts Poly (caprolactone) triol with hydroxyl value of about 195.2 12.73 parts Catalyst 6.0 × 10 ^-3 parts 1,4-Butanediol 11.45 parts H ₁₂ MDI 61.30 parts Average hydroxyl value of polyol 88.3 Sheet thickness 0.7mm Elongation 504% Breaking strength 707kg / cm ² Tear strength 48kg / cm A-6 Poly (1,6-hexanecarbonate) diol 43.44 parts with a hydroxyl value of about 53.3 Poly (caprolactone) diol 68.27 parts with a hydroxyl value of about 91.1 68. .2 poly (caprolactone) triol 12.41 parts catalyst 6.0 × 10 ^-3 parts 1,4-butanediol 12.41 parts H ₁₂ MDI 63.46 parts average hydroxyl value of polyol 88.3 sheet thickness 0.7 mm elongation 520% breaking strength 637 kg / cm ² Tear strength 56kg / cm A-7 Poly (1,6-hexane / 1.4-dimethylenecyclohexanecarbonate) diol with a hydroxyl value of about 128.6 [Polycarbonate diol obtained by using 1,6-hexanediol and cyclohexanedimethanol as raw material diol] 22.40 parts Poly (1,6-hexanecarbonate) diol with a hydroxyl value of about 55.87 22.40 parts Poly (caprolactone) diol with a hydroxyl value of about 91.1 70.41 parts Poly (caprolactone) triol with a hydroxyl value of about 195.2 12.80 parts Catalyst 6.0 × 10 ^-3 parts 1,4-Butanediol 10.24 parts H ₁₂ MDI 61.74 parts Average hydroxyl value of polyol 101.9 Sheet thickness 0.7mm Elongation 399% Breaking strength 754kg / cm ² Tear strength 53kg / cm A-8 Poly (1,6-hexane / 1.4-dimethylenecyclohexanecarbonate) diol with a hydroxyl value of about 128.6 21.85 parts Poly (1,6-hexanecarbonate) diol with a hydroxyl value of about 55.87 21.85 parts Poly (1) with a hydroxyl value of about 91.1 Caprolactone) Triol 68.66 parts Poly (caprolactone) triol having a hydroxyl value of about 195.2 12.48 parts Catalyst 6.0 × 10 ^-3 parts 1,4-butanediol 11.24 parts H ₁₂ MDI 63.93 parts Average hydroxyl value of polyol 101.9 Sheet thickness 0.7mm elongation 387% Breaking strength 626kg / cm ² Tear strength 45kg / cm

Claims (4)

[Claims] 1. A cross-linked polyurethane resin sheet having self-healing property, at least one surface of which is surface-modified by impregnation curing of at least one unsaturated compound selected from acrylic acid ester and methacrylic acid ester, and A surface-modified cross-linked polyurethane resin sheet whose surface-modified surface retains self-repairing properties. 2. The sheet according to claim 1, which is cured by irradiation with energy rays. 3. The sheet according to claim 1, wherein the cross-linked polyurethane resin before surface modification has an elongation of about 250% or more and a breaking strength of about 300 kg / cm ² or more. 4. The crosslinkable polyurethane resin comprises a diol and a polyol having a valence of 3 or more, and the equivalent ratio of (polyol having a valence of 3 or more) / (diol) is about 0.1 to 0.6 and the average hydroxyl value is about 70 to 150. Of a relatively high molecular weight polyol (A), a substantially divalent chain extender (B), and about 0.8 to 1.2 equivalents of the substantially divalent chain extender with respect to the total of the polyol (A) and the chain extender. The sheet according to claim 3, which is a cross-linked polyurethane-based resin obtained by reacting the polyisocyanate compound (C).