JP2014221852A - Composition for surface protective coating and base material with surface protective layer formed thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a surface protective coating with which a coating film excellent in self-repairing property, scratch resistance, blocking resistance, and resistance to yellow discoloration by heat can be formed, and to provide a base material with a surface protective layer formed thereon by the composition.SOLUTION: The invention discloses: a composition for a surface protective coating which is a composition containing (A) a condensation product obtained by hydrolyzing and condensing thiol group-containing alkoxysilanes (a1) represented by general formula RSi(OR)(Rrepresents a 1-8C aliphatic hydrocarbon group having at least one thiol group or a 6-12C aromatic hydrocarbon group having at least one thiol group, and Rrepresents a hydrogen atom or a 1-4C aliphatic hydrocarbon group), and (B) polyfunctional olefins, and of which the cured product has a temperature with the maximum tan δ in a range of 25-60°C when subjected to dynamic viscoelasticity measurement of 10 Hz; and a base material with a surface protective layer formed thereon by the coating agent.

Description

  The present invention relates to a surface protective coating composition and a substrate on which a surface protective layer is formed.

  Home appliances such as refrigerators, microwave ovens, washing machines, woodworking products such as furniture, mobile phones, personal computers, displays, information devices such as touch panels, electronic parts such as solar cells, interior and exterior of vehicles such as automobiles and motorcycles Such various industrial products may cause scratches on the surface during transportation or use. In order to prevent scratches and protect the aesthetic appearance of the surface, it is important to provide a surface protective coating layer. For this purpose, a method of hard-coating the surface of a product member with an active energy ray-curable resin or the like may be used. However, since the coating film shrinks during curing, adhesion to the substrate may be insufficient, or cracks may occur because the coating film is hard and brittle. Further, in applications that require secondary processing after coating, there are cases where contradictory performances such as flexibility, followability, flexibility, etc. are required without being brittle.

  Therefore, there is a method of providing scratch resistance by providing a so-called self-repairing coating layer on the surface. Various self-healing coating agents are known. For example, Patent Documents 1 to 3 use a thermosetting coating composition of polyester and polyol, and Patent Documents 4 and 5 use an ultraviolet curable urethane acrylate. Patent Document 6 discloses a coating composition using an ultraviolet curable epoxy resin, oxetane resin, or vinyl ether resin.

  Among these self-healing coating agents, the thermosetting coating composition can be damaged by heat when the substrate is a plastic film, and it is efficient because the curing time is relatively long. There is a problem that a coating film cannot be produced. The coating composition using UV curable urethane acrylate has a problem that the absolute hardness of urethane acrylate as a skeleton is insufficient, and scratches made of hard materials on the obtained coating film are difficult to recover. is there. Moreover, the obtained coating film generally has a high blocking property and is difficult to superimpose. Furthermore, there is a problem that yellowing easily occurs at high temperatures due to low heat resistance. A coating composition using an ultraviolet curable epoxy resin, oxetane resin, or vinyl ether resin has a problem that it cannot efficiently form a coating film because post-curing is required.

  On the other hand, as an ultraviolet curable resin composition, there is one utilizing a reaction (ene-thiol reaction) between a compound having a carbon-carbon double bond and a compound having a thiol group. The ene-thiol reaction has advantages such that it proceeds by ultraviolet irradiation regardless of the presence or absence of a polymerization initiator, is not subject to reaction inhibition by oxygen, and has a small curing shrinkage. Regarding a curing method and a cured product using this reaction, use of an unsaturated thiol compound having a carbon-carbon double bond and a thiol group in one molecule (for example, see Patent Document 7), carbon- A resin composition composed of a compound having a plurality of carbon double bonds and a compound having a plurality of thiol groups (for example, see Patent Documents 8 to 11) has been proposed. However, the cured product obtained by the ene-thiol reaction lacks absolute hardness, and when the substrate to be coated is hard, there is a problem that the coating film obtained by the substrate is destroyed. Moreover, the obtained coating film generally has a high blocking property and is difficult to superimpose.

  The present inventors also referred to a so-called random silsesquioxane having a thiol group containing sulfur (an alkoxysilyl group or a silanol group remaining) and an organic substance having a carbon-carbon double bond as an ene-thiol. The organic-inorganic hybrid hardened | cured material obtained by making it react (patent document 12) was proposed. Although the cured product is excellent in heat resistance and has a high refractive index because it contains sulfur, there is no description or suggestion in the literature that the cured product has self-healing properties.

JP2012-107101A JP2012-121985A JP 2012-140614 A JP 2010-260905 A JP 2013-049839 A JP 2007-284613 A JP 49-51333 A JP-A-49-54491 JP 50-27836 A JP-A-53-134096 JP 2003-295431 A JP 2007-291313 A

  The present invention is capable of forming a self-healing coating film, and the coating film is excellent in scratch resistance, blocking resistance, heat yellowing resistance, and an active energy ray-curable composition for surface protective coating, and An object of the present invention is to provide a substrate (coated article) on which a surface protective layer is formed by painting and curing the composition for surface protective coating.

  The present inventor has intensively studied to solve the above problems, and as a result, a specific silane compound, a composition containing a compound having a specific carbon-carbon double bond, or a specific silane compound, a specific carbon-carbon. A composition containing a compound having a double bond and a specific organic polyfunctional thiol compound, and the obtained cured product has a temperature at which tan δ is maximized when measured at a dynamic viscoelasticity of 10 Hz is 25 to 60 ° C. If it is in the range, it has been found that the above problems can be solved, and based on this, the present invention has been completed.

  The present invention provides the following surface protective coating agent and a substrate with a protected surface obtained by using the surface protective coating agent.

1. (A) General formula (1)
R ¹ Si (OR ² ) ₃ (1)
(Wherein R ¹ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms having at least one thiol group or an aromatic hydrocarbon group having 6 to 12 carbon atoms having at least one thiol group, and R ² represents A hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.) A condensate obtained by hydrolysis and condensation of a thiol group-containing alkoxysilane (a1) represented by: and (B) a polyfunctional olefin A composition comprising
A composition for surface protective coating, wherein a temperature at which tan δ is maximized when the obtained cured product is measured by dynamic viscoelasticity at 10 Hz is in a range of 25 to 60 ° C.

  2. The surface protection according to item 1, wherein the condensate (A) is obtained by hydrolysis and condensation of a metal alkoxide (a2) having no thiol group together with the thiol group-containing alkoxysilane (a1). Coating composition.

  3. Item 3. The surface protective coating composition according to Item 1 or 2, wherein the polyfunctional olefin (B) is a polyfunctional arylate and / or a polyfunctional urethane acrylate.

  4). The composition for surface protective coating according to any one of Items 1 to 3, further comprising (C) an organic polyfunctional thiol compound.

  5. Item 5. The surface protective coating composition according to Item 4, wherein the organic polyfunctional thiol compound (C) is an aliphatic ester polyfunctional thiol compound.

  6). Item 1 or 2 above, wherein the use ratio of the condensate (A) is 5 to 75% by weight based on the total of 100% by weight of the condensate (A) and the polyfunctional olefins (B). 4. The composition for surface protective coatings according to 3.

  7). The use ratio of the condensate (A) is 5 to 75% by weight based on the total 100% by weight of the condensate (A), the polyfunctional olefins (B) and the organic polyfunctional thiol compound (C). Item 6. The composition for surface protective coating according to Item 4 or 5 above.

  8). 8. A substrate having a surface protective layer formed by coating and curing the surface protective coating composition according to any one of Items 1 to 7 on a part or all of the surface of the substrate.

  9. A laminate in which a substrate is plate-like and a surface protective layer formed by coating and curing the surface protective coating composition according to any one of Items 1 to 7 on one or both surfaces of the substrate. .

  According to the present invention, the surface protective coating containing the condensate (A) and the polyfunctional olefins (B), or the condensate (A), the polyfunctional olefins (B), and the organic polyfunctional thiol compound (C). Based on the fact that the temperature at which tan δ is maximum when the obtained cured product is measured at a dynamic viscoelasticity of 10 Hz is in the range of 25 to 60 ° C., the following remarkable An effect is produced.

  (1) The composition for surface protective coating of the present invention can form a coating film having excellent self-repairing property by active energy ray curing, and the coating film has scratch resistance, blocking resistance, Excellent heat-resistant yellowing.

  (2) The composition for surface protective coating of the present invention can be easily applied to a substrate on which a surface protective layer is formed by coating various active materials such as plastics, metals, and glass, and then curing with active energy rays. Can be produced. Moreover, when a base material is plate shape, the laminated body by which the surface protection layer was formed in the single side | surface or both surfaces of the substrate surface can be produced easily.

  (3) The composition for surface protective coating of the present invention includes, for example, household appliances such as refrigerators, microwave ovens and washing machines; woodwork products such as furniture; information devices such as mobile phones, personal computers, displays and touch panels; solar cells It is possible to effectively prevent scratches on the surface of various substrates such as the interior and exterior of vehicles such as automobiles and motorcycles. The laminate obtained by the present invention includes, for example, a housing for home appliances such as a refrigerator, a microwave oven, and a washing machine; a woodwork product such as furniture; a housing for a mobile phone; a housing for a personal computer; Information devices such as the surface of the touch panel; electronic components such as the surface of solar cells; suitably used for effectively preventing scratches on various substrate surfaces such as interior and exterior components of vehicles such as automobiles and motorcycles. it can.

18 is a photograph of an atomic force microscope (AFM) phase image of a coating film surface of a laminate obtained in Example 16. 10 is a photograph of an atomic force microscope (AFM) phase image of a coating film surface of a laminate obtained in Comparative Example 8.

Composition for surface protective coating The composition for surface protective coating of the present invention comprises a condensate (A) and a polyfunctional olefin (B), or a condensate (A), a polyfunctional olefin (B) and an organic polyfunctional thiol. It is a composition for surface protective coating containing the compound (C), and the temperature at which tan δ is maximum when the obtained cured product is measured at a dynamic viscoelasticity of 10 Hz is in the range of 25 to 60 ° C. It is characterized by being.

Condensate (A)
The condensate (A) used in the present invention is a compound obtained by hydrolysis and condensation of thiol group-containing alkoxysilanes (a1). Specific examples of the component (a1) include, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropyltributoxysilane, 1,4-dimercapto- 2- (trimethoxysilyl) butane, 1,4-dimercapto-2- (triethoxysilyl) butane, 1,4-dimercapto-2- (tripropoxysilyl) butane, 1,4-dimercapto-2- (tributoxy) Silyl) butane, 2-mercaptomethyl-3-mercaptopropyltrimethoxysilane, 2-mercaptomethyl-3-mercaptopropyltriethoxysilane, 2-mercaptomethyl-3-mercaptopropyltripropoxysilane, 2-mercaptomethyl-3- Mercaptop Piltoriboxysilane, 1,2-dimercaptoethyltrimethoxysilane, 1,2-dimercaptoethyltriethoxysilane, 1,2-dimercaptoethyltripropoxysilane, 1,2-dimercaptoethyltributoxysilane, etc. The exemplified compounds can be used alone or in appropriate combination. Among the exemplified compounds, 3-mercaptopropyltrimethoxysilane is particularly preferable because of high reactivity of hydrolysis reaction and easy availability.

  The condensate (A) used in the present invention is a compound obtained by hydrolysis and condensation of a mixture of thiol group-containing alkoxysilanes (a1) and metal alkoxides (a2) having no thiol group. May be. Specific examples of the component (a2) include, for example, trialkylalkoxysilanes such as trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, triphenylmethoxysilane, triphenylethoxysilane; dimethyldimethoxysilane, dimethyl Dialkyl dialkoxysilanes such as diethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane; Methoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane Alkyl trialkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane; tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxy Tetraalkoxy titaniums such as titanium; metal alkoxides such as tetraalkoxy zirconiums such as tetraethoxy zirconium, tetrapropoxy zirconium and tetrabutoxy zirconium may be used. The component (a2) can be used either alone or in combination of two or more. Of these, the crosslink density of the component (A) can be adjusted by using trialkylalkoxysilanes, dialkyldialkoxysilanes, and tetraalkoxysilanes. By using alkyltrialkoxysilanes, the amount of thiol groups contained in the condensate (A) can be adjusted. By using tetraalkoxy titanium and tetraalkoxy zirconium, the refractive index of the finally obtained cured product can be increased.

  When component (a1) and component (a2) are used in combination, [number of moles of thiol group contained in component (a1)] / [total number of moles of component (a1) and component (a2)] (molar ratio: 1 The average number of thiol groups contained per molecule) is an element that determines the amount of component (A) in the surface protective coating agent. As will be described later, there is an appropriate range for the amount of carbon-carbon double bonds contained in the component (B) with respect to one thiol group. Therefore, if the numerical value is large, the amount of the thiol group is increased, so that the required amount of the corresponding component (B) is increased, and the content of the component (A) is inevitably reduced. Conversely, if it is small, the amount of the thiol group decreases, so that the required amount of the corresponding component (B) decreases, and the content of the component (A) inevitably increases. For this reason, what is necessary is just to determine the said numerical value arbitrarily according to content of the component (A) to require. However, from the viewpoint of surface hardness and blocking resistance, the numerical value is preferably 0.5 or more. When it is less than 0.5, the number of thiol groups contained in the component (A) to be obtained decreases, so that the crosslink density in the ene-thiol reaction decreases. In such a case, the obtained coating film becomes fragile, and the surface hardness and blocking resistance tend to decrease. [Total number of moles of each alkoxy group contained in component (a1) and component (a2)] / [Total number of moles of component (a1) and component (a2)] (molar ratio: alkoxy contained per molecule) The average number of groups) is preferably 2.5 or more and 3.5 or less, and more preferably 2.7 or more and 3.2 or less. When the numerical value is 2, it becomes silicone, that is, a rubber-like substance. Therefore, when it is less than 2.5, the rubber-like property becomes too strong, and the surface hardness of the obtained coating film tends to decrease. Moreover, when it exceeds 3.5, when manufacturing a component (A), it exists in the tendency which becomes easy to gelatinize.

  The condensate (A) used in the present invention can be obtained by condensing component (a1) alone or in combination with component (a2), condensing them after hydrolysis. By the hydrolysis reaction, the alkoxy group contained in component (a1) or component (a2) becomes a hydroxyl group, and alcohol is by-produced. The amount of water required for the hydrolysis reaction is [number of moles of water used in hydrolysis reaction] / [total number of moles of each alkoxy group contained in component (a1) and component (a2)] (molar ratio). .2 or more and 1.5 or less is sufficient. When it is less than 0.2, the molecular weight of the finally obtained component (A) becomes too low, and the curability tends to decrease. Moreover, when it exceeds 1.5, since the quantity of the water which should be removed in the case of the condensation reaction (dehydration reaction) performed later increases, it is economically disadvantageous.

  In addition, when the component (a2) is used in combination with a tetraalkoxytitanium, a tetraalkoxyzirconium or the like, particularly a metal alkoxide having a high hydrolyzability and condensation reactivity, the hydrolysis and condensation reaction proceeds rapidly, and the system May gel. In this case, gelation can be avoided by adding the component (a2) after the hydrolysis reaction of the component (a1) has been completed and all water has been consumed.

  The catalyst used for the hydrolysis reaction is not particularly limited, and a conventionally known hydrolysis catalyst can be arbitrarily used. Of these, formic acid is preferred because it has high catalytic activity and also functions as a catalyst for the subsequent condensation reaction. The amount of formic acid added is preferably 0.1 to 25 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight as the total of component (a1) and component (a2). When the amount is more than 25 parts by weight, the stability of the resulting surface protective coating composition tends to decrease, and even if formic acid can be removed in a subsequent step, the removal amount increases. On the other hand, when the amount is less than 0.1 parts by weight, the reaction does not substantially proceed or the reaction time tends to be long. The reaction temperature and time can be arbitrarily set according to the reactivity of the component (a1) or component (a2), but are usually about 0 to 100 ° C., preferably about 20 to 60 ° C. and about 1 minute to 2 hours. is there. The hydrolysis reaction can be performed in the presence or absence of a solvent. The type of the solvent is not particularly limited, and one or more arbitrary solvents can be selected and used, but it is preferable to use the same solvent as that used in the condensation reaction described later. When the reactivity of component (a1) or component (a2) is low, it is preferable to carry out without solvent.

  The hydrolysis reaction is carried out by the above method, but the [number of moles of hydroxyl group formed by hydrolysis] / [total number of moles of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) is 0. It is preferable to make it progress so that it may become 3 or more, and it is still more preferable to adjust to 0.5 or more.

  In the condensation reaction, water is by-produced between the hydroxyl groups, and alcohol is by-produced between the hydroxyl group and the alkoxy group to form a siloxane bond. A conventionally known dehydration condensation catalyst can be arbitrarily used for the condensation reaction. As described above, formic acid is preferable because it has high catalytic activity and can be used as a catalyst for hydrolysis reaction. The reaction temperature and time can be arbitrarily set according to the reactivity of the component (a1) or component (a2), but are usually about 40 to 150 ° C., preferably about 60 to 100 ° C., about 30 minutes to 12 hours. It is.

  The condensation reaction is carried out by the above method. [Total number of moles of unreacted hydroxyl group and unreacted alkoxy group] / [Total number of moles of alkoxy groups contained in component (a1) and component (a2)] (molar ratio ) Is preferably adjusted to 0.4 or less, and more preferably adjusted to 0.3 or less. When it exceeds 0.4, the molecular weight of the component (A) obtained is small, the number of thiol groups per molecule decreases, the crosslinking density decreases, and as a result, the performance of the cured product tends to be impaired.

  The condensation reaction is preferably performed by diluting the solvent so that the concentration of component (a1) (or both when component (a2) is used in combination) is about 2 to 80% by weight. It is more preferable. It is preferable to use a solvent having a boiling point higher than that of water and alcohol generated by the condensation reaction because these can be distilled off from the reaction system. When the concentration is 2% by weight or more, the amount of the component (A) contained in the surface protective coating agent to be obtained is increased, so that the effect of the present invention becomes remarkable, which is preferable. By setting it to 80% by weight or less, the reaction can proceed stably, and the molecular weight of the component (A) to be produced is appropriate, so that the storage stability of the resulting surface protective coating agent is good. As a solvent to be used, one or more arbitrary solvents can be selected and used. It is preferable to use a solvent having a boiling point higher than that of water and alcohol produced by the condensation reaction because these can be distilled off from the reaction system. Moreover, a component (B) and a component (C) can also be used as a part of solvent.

  It is preferable to remove the used catalyst after completion of the condensation reaction because the stability of the resulting surface protective coating agent is improved. The removal method can be appropriately selected from various known methods depending on the catalyst used. For example, when formic acid is used, it can be easily removed by a method such as heating to above the boiling point or depressurization after completion of the condensation reaction, and formic acid is also preferred in this respect.

Polyfunctional olefins (B)
The polyfunctional olefin (B) used in the present invention is not particularly limited, and a conventionally known compound having a functional group related to a carbon-carbon double bond can be appropriately used. Examples of the functional group related to the carbon-carbon double bond include a vinyl group, an acryloyl group, a methacryloyl group, and an allyl group.

  Among these, the ene-thiol reaction is performed so that the functional group having a carbon-carbon double bond is polymerized with each other in preference to the reaction between the functional group having a carbon-carbon double bond and the thiol group. Those having high reactivity and those having low radical polymerizability are preferably used. Examples of such component (B) include those having an allyl group and urethane acrylates.

  As the compound having an allyl group, a compound having 2 or more, preferably 2 to 3 or more allyl groups can be suitably used. Examples of the compound having two allyl groups include diallyl phthalate, diallyl isophthalate, diallyl naphthalate, diallyl cyanurate, diallyl isocyanurate, pentaerythritol diallyl ether, trimethylolpropane diallyl ether, glyceryl diallyl ether, bisphenol A diallyl ether Bisphenol F diallyl ether, ethylene glycol diallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, propylene glycol diallyl ether, dipropylene glycol diallyl ether, tripropylene glycol diallyl ether, diallyl diphenate and the like. Examples of the compound containing three or more allyl groups include triallyl isocyanurate, pentaerythritol triallyl ether, pentaerythritol tetraallyl ether, trimethylolpropane triallyl ether, triallyl phosphite and the like. These compounds can be used either alone or in combination. Among these, triallyl isocyanurate, diallyl phthalate, diallyl diphenate, and pentaerythritol triallyl ether are particularly preferable. A compound having one allyl group can be used in combination with a compound having two or more allyl groups. Examples of the compound containing one allyl group include monoallyl cyanurate, monoallyl isocyanurate, pentaerythritol monoallyl ether, trimethylolpropane monoallyl ether, glycerin monoallyl ether, bisphenol A monoallyl ether, and bisphenol F mono. Examples include allyl ether, ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, triethylene glycol monoallyl ether, propylene glycol monoallyl ether, dipropylene glycol monoallyl ether, and tripropylene glycol monoallyl ether.

  As the urethane acrylates, polyfunctional urethane acrylates having two or more acryloyl groups or methacryloyl groups can be suitably used. Specific examples include those obtained by reacting a polyisocyanate compound with a hydroxyl group-containing acrylate compound, and those obtained by reacting a polyol compound, a polyisocyanate compound and a hydroxyl group-containing acrylate compound. Examples of the polyol compound include polyester polyol, polyether polyol, caprolactone diol, and the like. Examples of polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate. Examples thereof include nate and isophorone diisocyanate. Examples of the hydroxyl group-containing acrylate compound include 2-hydroxy acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 1,6-hexanediol monoacrylate, pentaerythritol triacrylate, and the like. These compounds can be used either alone or in combination.

  As the polyfunctional olefins (B), the above-mentioned various compounds can be used alone or in combination of two or more.

  When using component (B), [number of moles of carbon-carbon double bond contained in component (B)] / [number of moles of component (B)] (carbon-carbon double bond contained per molecule) Is preferably 2 or more. When it is less than 2, the curability of the surface protective coating agent is lowered, and the crosslink density of the obtained cured product is lowered, so that the physical properties such as the surface hardness of the cured product tend to be lowered. When using several types together as a component (B), what is necessary is just to satisfy | fill the said numerical value as the average.

  [Component (B) component (B) number of carbon-carbon double bonds contained in one molecule] / [molecular weight of component (B)] (indicating the concentration of carbon-carbon double bonds) (B ) Can increase the temperature of tan δ described later. Further, when a component having a small numerical value is used, the temperature of tan δ can be lowered. Although there is an influence of the molecular structure other than the carbon-carbon double bond, it cannot be said unconditionally. However, when it is desired to increase the temperature of tan δ, it is 8 mmol / g or more. What is necessary is just to make it g or less. By using a plurality of types as the component (B), the adjustment of the numerical value becomes easy.

Organic polyfunctional thiol compound (C)
The organic polyfunctional thiol compound (C) used in the present invention is not particularly limited, and a conventionally known compound having a thiol group can be appropriately used. Specifically, as those having a primary thiol group, for example, methyl-3-mercaptopropionate, 2-ethylhexyl-3-mercaptopropionate, n-octyl-3-mercaptopropionate, methoxy Butyl-3-mercaptopropionate, stearyl-3-mercaptopropionate, trimethylolpropane tris (3-mercaptopropionate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, pentaerythritol Aliphatic ester thiols such as tetrakis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), and ethanethiol , 1,2 Ethanedithiol, propanethiol, 1,3-propanedithiol, butanethiol, 1,4-butanedithiol, hexanethiol, 1,6-hexanedithiol, octanethiol, 1,8-octanedithiol, cyclohexanethiol, 1,2 -Cyclohexanedithiol and the like. Examples of those having a secondary thiol group include pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3 -Aliphatic ester thiols such as mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,3-butanedithiol, -Butanethiol, cyclohexyl mercaptan, cyclopentanethiol, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, Examples include pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis (3-mercaptobutyryloxy) butane, and the like. That. A component (C) can be used individually or in combination of 2 or more types. Among these, since a compound having only one thiol group in the molecule does not cause cross-linking between molecules, the effect of improving physical properties such as heat resistance and surface hardness of the cured product tends to be insufficient. For this reason, a compound having two or more thiol groups in the molecule is preferable. Particularly, aliphatic ester-based thiol compounds are commercially available in various structures, are easily available, have a low specific odor, or Since it is generally liquid, it is preferable because it is easy to blend. In the present invention, the secondary thiol group refers to a functional group represented by HS-CHXY (wherein X and Y represent functional groups other than H).

  The surface protective coating agent of the present invention contains the condensate (A) and polyfunctional olefins (B) described above as essential components, and an organic polyfunctional thiol compound (C) as necessary.

  It is necessary to adjust the usage-amount of each component according to the characteristic of the hardened | cured material obtained. Specifically, when dynamic viscoelasticity measurement is performed at 10 Hz, the temperature at which tan δ is maximized needs to be in the range of 25 to 60 ° C. The dynamic viscoelasticity measurement may be performed according to JIS K 7244-4. When the said temperature is less than 25 degreeC, the surface hardness of the hardened | cured material obtained becomes low too much, and there exists a tendency for destruction generate | occur | produces with respect to a low stress, and a permanent flaw is easy to generate | occur | produce. On the other hand, when the temperature exceeds 60 ° C., the surface hardness becomes too high, the stress is not relaxed, and there is a tendency that permanent damage is likely to occur due to destruction. If it is within the temperature range, generally, the lower the temperature, the higher the self-repairing property, and the higher the temperature, the higher the surface hardness tends to be. In order to develop self-healing properties, it is considered that a structure showing an elastic property and a structure showing a viscous property are mixed. Although the reason is not clear, when the condensate (A) is contained and the temperature at which tan δ is maximized is in the range of 25 to 60 ° C., it is presumed that the mixed structure described above is easily taken.

  Further, among the contents of the respective components of the composition for surface protective coating of the present invention, the condensate is from the viewpoint of excellent anti-blocking properties, heat-resistant yellowing and self-healing properties of the coating film. The content of (A) is important. That is, based on the total of 100% by weight of the condensate (A) and the polyfunctional olefins (B), or the sum of the condensate (A), the polyfunctional olefins (B), and the organic polyfunctional thiol compound (C). Based on 100% by weight, it is preferable that the content of the condensate (A) is about 5 to 75% by weight because the coating film has excellent blocking resistance, heat yellowing and self-repairing properties. . When the content of the condensate (A) is less than about 5% by weight, blocking resistance and heat yellowing tend to decrease. Moreover, when it exceeds about 75 weight%, there exists a tendency for self-repairing property to become difficult to express.

  Regarding the content of the condensate (A), when the content of the condensate (A) increases, the temperature at which tan δ becomes maximum tends to increase. In such a case, as described above, the temperature can be lowered by using a component having a low carbon-carbon double bond concentration in the component (B). On the other hand, when the content of the condensate (A) is small, the temperature at which tan δ becomes maximum tends to be low. In such a case, as described above, the temperature can be lowered by using a component having a high carbon-carbon double bond concentration in the component (B). On the other hand, when the use ratio of the condensate (A) increases, even if the temperature at which tan δ is maximized is lowered, a good surface hardness tends to be exhibited. Therefore, the specific blending amount depends on the types of the components (A), (B) and (C), but the temperature is lower and the blending amount of the component (A) may be increased. preferable.

  Furthermore, the amount of each component used is such that [(number of double bonds contained in component (B))] / [(number of thiol groups contained in component (A))] is 0.8 to 1. It is necessary to adjust so that it may be set to about 2, and it is preferable to set it as 0.9-1.1. When component (C) is used, [(number of double bonds contained in component (B))] / [(number of thiol groups contained in component (A)) + (component (C It is necessary to adjust so that the number of thiol groups contained in]) is 0.8 to 1.2, preferably 0.9 to 1.1. If the value is less than 0.9, a thiol group may remain and may cause malodor due to its decomposition. If it exceeds 1.1, a double bond remains after curing, and heat yellowing decreases. Tend.

  In the composition for surface protective coating of the present invention, a polymerization initiator can be used as necessary. It does not specifically limit as a polymerization initiator, A conventionally well-known photocationic initiator, photoradical initiator, etc. can be selected arbitrarily. Examples of the photocation initiator include sulfonium salts, iodonium salts, metallocene compounds, benzoin tosylate, and the like, which are compounds that generate an acid upon irradiation with active energy rays. Examples of such commercially available products include Cyracure UVI-6970. , UVI-6974, UVI-6990 (product names manufactured by Union Carbide, USA), Irgacure 264 (manufactured by Ciba Specialty Chemicals), CIT-1682 (manufactured by Nippon Soda Co., Ltd.), and the like. The amount of the cationic photopolymerization initiator used is usually preferably about 2% by weight or less, more preferably about 0.01 to 0.5% by weight, based on 100% by weight of the composition for surface protective coating. preferable. Examples of the photo radical initiator include Darocur 1173, Irgacure 651, Irgacure 184, Irgacure 907 (all trade names manufactured by Ciba Japan Co., Ltd.), benzophenone, and the like. Usually, it is preferably about 2% by weight or less, more preferably about 0.01 to 0.5% by weight based on the weight percent. In addition, when there is a concern about a decrease in the weather resistance of the resulting cured product, particularly when used for an optical member that requires high weather resistance and transparency, it is better not to use a photoreaction initiator or a photosensitizer. Good.

  Moreover, in order to further improve the stability of the composition for surface protective coating, a compound that suppresses the ene-thiol reaction can be blended. Examples of such compounds include phosphorus compounds such as triphenylphosphine and triphenyl phosphite; p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert) -Butylphenol), N-nitrosophenylhydroxylamine aluminum salt, diphenylnitrosamine and other radical polymerization inhibitors; benzyldimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol, Tertiary amines such as diazabicycloundecene; 2-methylimidazole And imidazoles such as 2-ethyl-4-methylimidazole, 2-ethylhexylimidazole, 2-undecylimidazole, and 1-cyanoethyl-2-methylimidazole.

  Among the phosphorus compounds, triphenyl phosphite is preferable because it has a high inhibitory effect on the ene-thiol reaction, is liquid at room temperature, and is easy to handle. The amount of the compound to be blended in the surface protective coating composition is usually preferably about 0.1 to 10% by weight based on 100% by weight of the surface protective coating composition. When it is less than 0.1% by weight, the effect of suppressing the ene-thiol reaction is insufficient, and when it exceeds 10% by weight, the remaining amount in the obtained cured product is increased and the physical properties of the cured product are deteriorated. Tend.

  Of the radical polymerization inhibitors, nitrosophenylhydroxylamine aluminum salt is preferable because it has a high inhibitory effect on the ene-thiol reaction even in a small amount and is excellent in the color tone of the resulting cured product. The amount of the compound to be blended in the surface protective coating agent is usually preferably about 0.0001 to 0.1% by weight based on 100% by weight of the composition for surface protective coating. When it is less than 0.0001% by weight, the effect of suppressing the ene-thiol reaction is insufficient, and when it exceeds 0.1% by weight, the active energy ray curability tends to be lowered.

  Of the tertiary amines, benzyldimethylamine is preferable because it has a high inhibitory effect on the ene-thiol reaction even in a small amount and is liquid at room temperature and easy to handle. The amount of the compound to be blended in the surface protective coating agent is usually preferably about 0.001 to 5% by weight based on 100% by weight of the composition for surface protective coating. When the amount is less than 0.001% by weight, the effect of suppressing the ene-thiol reaction may be insufficient. When the amount exceeds 5% by weight, unreacted hydroxyl groups and alkoxy groups in component (A) are condensed. There is a tendency to react and gel.

  Moreover, a solvent can be mix | blended with the composition for surface protection coatings of this invention as needed. A conventionally known solvent can be arbitrarily used as the solvent, but it is preferable to use a solvent that easily volatilizes so that it can be volatilized before curing with active energy rays.

  Moreover, the composition for surface protective coatings of this invention is another aspect. WHEREIN: After hydrolyzing a component (a1) and arbitrary component (a2) in presence of formic acid, a solvent, a component (B), and / or a component. It can also be obtained by a condensation reaction in the presence of (C). Conditions such as reaction temperature, reaction time, and solvent type are all the same as in the case of the component (A).

  Furthermore, the composition for surface protective coating used in the present invention includes a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, and a lubricant as long as the effects of the present invention are not impaired. Further, an antistatic agent, a brightening agent, a colorant, a conductive agent, a release agent, a surface treatment agent, a viscosity modifier, a filler, and the like may be blended.

  The surface protective coating composition thus obtained can be cured by irradiation with active energy rays and / or heating. The surface protective coating composition is a surface protective coating layer of a substrate having a surface protected according to the present invention.

  The base material with the surface protected of the present invention is obtained by applying the surface protective coating composition of the present invention on the base material and then curing the composition.

  Examples of the substrate to which the composition for surface protective coating of the present invention can be applied include inorganic materials such as glass and silicon; metal materials such as aluminum, stainless steel and copper; polyethylene terephthalate resin, polyester resin, polyimide resin, epoxy resin, Polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer resin, polyvinyl acetate resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polymethyl methacrylate resin, nylon resin, polycarbonate resin, polynorbornene Examples thereof include resin materials such as resin and triacetyl cellulose resin; various types of base materials obtained from various materials such as paper. The surface of these base materials may be treated by oxidation treatment, acid treatment, plasma treatment, discharge treatment or the like to improve the adhesion of the composition for surface protective coating. When the base material to which the composition for surface protective coating is applied is a plate-like substrate such as a film, sheet or board, the thickness of the substrate can be arbitrarily set because the composition is usually on the surface of the substrate. . An intermediate layer such as a resin layer that does not participate in the photoreaction may be provided between the surface protective coating composition and the substrate. As the intermediate layer, glass, metal silicon, polyethylene terephthalate resin or the like is preferable. In addition, as a base material, since it is easy to apply | coat the composition for surface protection coatings, it is preferable that it is substrates, such as a film and a sheet | seat.

The irradiation amount of the active energy ray is not particularly limited, and may be appropriately determined according to the type and thickness of the compound used in the surface protective coating agent. In the case of ultraviolet rays, for example, the integrated light amount is 50 to 10,000 mJ / Irradiation may be performed so as to be about cm ² . Moreover, when coating or filling with a thick film, it is preferable to improve photocurability by adding a photoreaction initiator or a photosensitizer to the composition as described above.

  Active energy rays used for curing include high energy ionizing radiation and ultraviolet rays. As the high-energy ionizing radiation source, for example, an electron beam accelerated by an accelerator such as a cockcroft accelerator, a handagraaf accelerator, a linear accelerator, a betatron, or a cyclotron is industrially most convenient and economical. In addition, radiation such as γ-rays, X-rays, α-rays, neutrons, and protons emitted from radioisotopes and nuclear reactors can also be used. Examples of the ultraviolet ray source include an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a carbon arc lamp, and a solar lamp. The irradiation time of the active energy ray is not particularly limited, and known conditions can be employed. When the composition for surface protective coating contains a solvent, it is usually irradiated with active energy rays after volatilizing the solvent. The method for volatilizing the solvent may be appropriately determined according to the type, amount, film thickness, etc. of the solvent, but it is heated to about 40 to 150 ° C., preferably about 60 to 100 ° C. The condition is about 2 hours.

  Moreover, the composition for surface protection coatings of this invention can also be heat-hardened after coating to various base materials. When heat-curing, a cured coating film can be formed by heating at about 60 to 150 ° C. for about 3 to 120 minutes. When performing heat curing, thermal polymerization initiators such as organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, and acetophenone compounds can also be used. When these catalysts are used, the amount is usually preferably about 2% by weight or less, more preferably about 0.01 to 0.5% by weight, based on 100% by weight of the composition for surface protective coating.

  Thus, the base material on which the surface protective layer is formed can be easily produced by coating the surface protective coating composition of the present invention on various base materials and curing the active energy ray or heat. . In this case, the film thickness of the cured coating film based on the composition of the present invention is not particularly limited, but it is usually preferably about 5 to 200 μm.

  Hereinafter, the present invention will be specifically described with reference to production examples, examples, and comparative examples. However, the present invention is not limited to these examples. In each example, both parts and% are based on weight.

Production Example 1 (Production of condensate (A-1))
In a reactor equipped with a stirrer, a condenser, a water separator, a thermometer and a nitrogen inlet, 500 parts of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name “KBM-803”), methyl Trimethoxysilane (“Methyltrimethoxysilane” manufactured by Tama Chemical Industry Co., Ltd.) 69.4 parts ([number of moles of thiol group contained in component (a1)] / [total of component (a1) and component (a2) Number of moles] = 0.83, [total number of moles of each alkoxy group contained in component (a1) and component (a2)] / [total number of moles of component (a1) and component (a2)] = 3), ion 165 parts of exchange water ([number of moles of water used for hydrolysis reaction] / [number of moles of alkoxy group contained in component (a1)] (molar ratio) = 1.0), 11.4 parts of 95% formic acid were charged. The hydrolysis reaction was performed at room temperature for 30 minutes. During the reaction, the temperature increased by 30 ° C. due to exotherm. After the reaction, 712 parts of toluene was charged and heated. When the temperature was raised to 71 ° C., methanol generated by hydrolysis and a part of toluene began to be distilled off. The temperature was raised to 75 ° C. over 2 hours, and the water was distilled off by condensation reaction. After further reacting at 75 ° C. for 1 hour, the pressure was reduced at 70 ° C. and 20 kPa to distill off a part of the remaining toluene, methanol, water, and formic acid. Furthermore, 377 parts of condensates (A-1) were obtained by depressurizing at 70 degreeC and 1 kPa, and distilling toluene off. [Mole number of unreacted hydroxyl group and alkoxy group] / [Mole number of alkoxy group contained in component (a1)] (molar ratio) was 0.10, and the concentration was 98.0%. The concentration of the thiol group in the condensate (A-1) was 6.44 mmol / g.

Production Example 2 (Production of condensate (A-2))
In the same reactor as in Production Example 1, 500 parts of 3-mercaptopropyltrimethoxysilane, 138 parts of ion-exchanged water ([number of moles of water used for hydrolysis reaction] / [each alkoxy group contained in component (a1)]) Total number of moles] (molar ratio) = 1.0) and 10.0 parts of 95% formic acid were charged and subjected to a hydrolysis reaction at room temperature for 30 minutes. During the reaction, the temperature rose by a maximum of 19 ° C. due to exotherm. After the reaction, 625 parts of toluene was charged and heated. When the temperature was raised to 72 ° C., part of methanol and toluene generated by hydrolysis began to be distilled off. The temperature was raised to 75 ° C. over 1 hour, and the water was distilled off by condensation reaction. After further reacting at 75 ° C. for 1 hour, the pressure was reduced at 70 ° C. and 20 kPa to distill off a part of the remaining toluene, methanol, water, and formic acid. Furthermore, 341 parts of condensates (A-2) were obtained by depressurizing at 70 degreeC and 1 kPa, and distilling toluene off. [Mole number of unreacted hydroxyl group and alkoxy group] / [Total mole number of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) is 0.12, and the concentration is 99.1%. there were. The concentration of the thiol group in the condensate (A-2) was 7.47 mmol / g.

Production Example 3 (Production of condensate (A-3))
In the same reaction apparatus as in Production Example 1, 500 parts of 3-mercaptopropyltrimethoxysilane and 173 parts of methyltrimethoxysilane ([number of moles of thiol group contained in component (a1)] / [component (a1) and component ( Total number of moles of a2) = 0.67, [Total number of moles of each alkoxy group contained in component (a1) and component (a2)] / [Total number of moles of component (a1) and component (a2)] = 3) 206 parts of ion-exchanged water ([number of moles of water used for hydrolysis reaction] / [total number of moles of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) = 1.0 ), 13.5 parts of 95% formic acid were charged and hydrolyzed at room temperature for 30 minutes. During the reaction, the temperature rose by a maximum of 37 ° C. due to exotherm. After the reaction, 842 parts of toluene was charged and heated. When the temperature was raised to 71 ° C., part of methanol and toluene generated by hydrolysis began to be distilled off. The temperature was raised to 75 ° C. over 1 hour, and the water was distilled off by condensation reaction. After further reacting at 75 ° C. for 1 hour, the pressure was reduced at 70 ° C. and 20 kPa to distill off a part of the remaining toluene, methanol, water, and formic acid. Furthermore, 599 parts of condensates (A-3) were obtained by depressurizing at 70 degreeC and 0.7 kPa and distilling toluene off. [Number of moles of unreacted hydroxyl group and alkoxy group] / [total number of moles of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) is 0.11, and the concentration is 98.9%. there were. Moreover, the density | concentration of the thiol group of a condensate (A-3) was 4.25 mmol / g.

Production Example 4 (Production of condensate (A-4))
In the same reactor as in Production Example 1, 500 parts of 3-mercaptopropyltrimethoxysilane, 69.4 parts of methyltrimethoxysilane ([number of moles of thiol group contained in component (a1)] / [component (a1) and Total number of moles of component (a2)] = 0.83, [Total number of moles of each alkoxy group contained in component (a1) and component (a2)] / [Total number of moles of component (a1) and component (a2) ] = 3), 248 parts of ion-exchanged water ([number of moles of water used for hydrolysis reaction] / [number of moles of alkoxy groups contained in component (a1)] (molar ratio) = 1.5), 95% formic acid 11.4 parts were charged and subjected to a hydrolysis reaction at room temperature for 30 minutes. During the reaction, the temperature rose up to 27 ° C due to exotherm. After the reaction, 712 parts of toluene was charged and heated. When the temperature was raised to 71 ° C., methanol generated by hydrolysis and a part of toluene began to be distilled off. The temperature was raised to 75 ° C. over 2 hours, and the water was distilled off by condensation reaction. After further reacting at 75 ° C. for 1 hour, the pressure was reduced at 70 ° C. and 20 kPa to distill off a part of the remaining toluene, methanol, water, and formic acid. Furthermore, 374 parts of condensates (A-4) were obtained by depressurizing at 70 degreeC and 1 kPa and distilling toluene off. [Mole number of unreacted hydroxyl group and alkoxy group] / [Mole number of alkoxy group contained in component (a1)] (molar ratio) was 0.04, and the concentration was 99.1%. The concentration of the thiol group in the condensate (A-4) was 6.50 mmol / g.

Examples 1 to 10 (Preparation of composition for surface protective coating)
With respect to 4.90 parts of the condensate (A-1) obtained in Production Example 1, diallyl diphenate (hereinafter referred to as DAD, manufactured by Nippon Distillation Co., Ltd.): trade name “DAD”, carbon-carbon as component (B) Concentration of double bond is 6.21 mmol / g) 5.10 parts ([number of moles of carbon-carbon double bond contained in component (B)) / [number of moles of thiol group contained in component (A)] (Molar ratio) = 1.00), and 0.05 part of hydroxycyclohexyl phenyl ketone (Ciba Japan Co., Ltd .: trade name “Irgacure 184”, hereinafter referred to as Irg184) as a photo-curing catalyst. Composition (D-1). Similarly, the condensates (A-1 to 4) obtained in Production Examples 1 to 4 were used to obtain surface protective coating compositions (D-2 to 10) according to Table 1. In Table 1, 550B: trifunctional urethane acrylate (manufactured by Arakawa Chemical Industries, Ltd .: trade name “Beam Set 550B”, concentration of carbon-carbon double bond is 2.25 mmol / g, TAIC: triallyl isocyanurate ( Nippon Kasei Co., Ltd .: trade name “Tyke”), carbon-carbon double bond concentration is 12.0 mmol / g, TMMP: trimethylolpropane tris (3-mercaptopropionate) (hereinafter TMMP, SC Organic) Chemical Co., Ltd .: Trade name (TMMP), thiol group concentration is 7.52 mmol / g).

Comparative Examples 1 to 4 (Preparation of composition for surface protective coating)
With respect to 6.51 parts of the condensate (A-3) obtained in Production Example 1, 3.49 parts of TAIC as the component (B) ([number of moles of carbon-carbon double bonds contained in the component (B)] / [Number of moles of thiol groups contained in component (A)] (molar ratio) = 1.00) and 0.05 part of Irg184 were used as a surface protective coating composition (d-1). Similarly, it was set as the composition for surface protection coatings (d-2-4) according to Table 1.

  Table 1 shows the composition of the components of the surface protective coating composition of each Example and each Comparative Example.

Examples 11 to 20 and Comparative Examples 5 to 8 (Preparation of laminates)
The surface protective coating composition (D-1) is coated on a glass substrate to a cured film thickness of 100 μm, and 365 nm using an ultraviolet irradiation device (USHIO INC., Trade name “UV-152”). The laminated body (E-1) in which the surface protective layer was formed was obtained by irradiating with an ultraviolet-ray so that an integrated light quantity may be set to 500 mJ / cm < ² > with the detector of. Similarly, the laminated body (E-2-10) in which the surface protective layer was formed using the composition for surface protective coatings (D-2-10) of Examples 2-10 was compared with Comparative Examples 1-4. Using the surface protective coating compositions (d-1 to 4), laminates (e-1 to 4) each having a surface protective layer were obtained.

Evaluation of self-healing property 100 g of a brass wire brush (TIGER channel brush brass wire ST # 147) in an environment of a temperature of 23 ° C. with respect to the coating surface of the laminate (E-1) obtained in Example 11. The film was rubbed back and forth 10 times while applying a load of 1, and the self-repairability of the scratches on the coating surface was judged according to the following criteria. The results are shown in Table 2. Similarly, the laminates (E-2 to 10) obtained in Examples 12 to 20 and the laminates (e-1 to 4) obtained in Comparative Examples 4 to 6 were also evaluated. The results are shown in Table 2.
○: Scratches disappeared within 5 minutes in an environment of 23 ° C.
Δ: Scratches disappeared within 10 seconds in a circulating drier set at 60 ° C.
X: In a circulating drier set at 60 ° C., it takes 15 seconds or more to disappear, or does not disappear.

Evaluation of surface hardness With respect to the coating film surface of the laminate (E-1) obtained in Example 11, the hardness of the pencil was determined in accordance with JIS K5600 so that the coating film was destroyed and could not be repaired at a load of 250 g. . The results are shown in Table 2. Similarly, the laminates (E-2 to 10) obtained in Examples 12 to 20 and the laminates (e-1 to 4) obtained in Comparative Examples 1 to 4 were also evaluated. The evaluation was performed according to the following criteria using a pencil of 2B to 8H (manufactured by Mitsubishi Pencil Co., Ltd .: trade name “Uni”).
2B to 8H: Indicates that the material is destroyed at 2B to 8H.
> 8H: Indicates that no destruction occurs even at 8H.

Measurement of dynamic viscoelasticity The composition for surface protection coating (D-1) was poured into an aluminum cup so as to have a film thickness of 80 μm, and an ultraviolet irradiation device (made by USHIO INC., Trade name “UV-152”) was used. Then, ultraviolet rays were irradiated with a 365 nm detector so that the integrated light amount was 350 mJ / cm ² to obtain a cured product. Similarly, a cured product was obtained using the compositions for surface protective coating (D-2 to 10) and (d-1 to 4). Each of the obtained cured products was cut into 5 mm × 30 mm, and tan δ using a viscoelasticity measuring device (manufactured by Seiko Instruments Inc., trade name “DMS6100”, measurement conditions: frequency 10 Hz, slope 3 ° C./min). Were measured and evaluated. The measurement results are shown in Table 2.

Heat resistance of cured film The laminate (E-1) obtained in Example 11 was heated at 180 ° C. for 2 hours, and the degree of coloring of the coated film after heating was visually evaluated. The evaluation criteria are as follows. Similarly, the laminates (E-2 to 10) obtained in Examples 12 to 20 and the laminates (e-1 to 4) obtained in Comparative Examples 5 to 8 were also evaluated. The results are shown in Table 2.
A: Almost no coloring.
○: Slightly colored.
Δ: Slightly colored (slightly yellow)
X: Dark coloring (yellow to brown).

Evaluation of blocking resistance The laminate (E-1) obtained in Example 10 was cut into 5 cm x 5 cm, a PET film was stacked on the coating surface, and a load of 1 kg was applied at 50 ° C for 1 minute. It was. Thereafter, the overlapped PET film was peeled off and the coating surface was observed. The evaluation criteria are as follows. Similarly, the laminates (E-2 to 10) obtained in Examples 12 to 20 and the laminates (e-1 to 4) obtained in Comparative Examples 5 to 8 were also evaluated. The results are shown in Table 2.
○: No trace is left.
Δ: There is tack when peeling, and a trace remains partially.
X: There is a strong tack and a trace remains on the entire surface.

  From the results of Table 2, the temperature when tan δ is maximized is in the range of 25 to 60 ° C., and each of the examples including the condensate (A) has both good surface hardness and self-repairability. In addition, it is clear that the heat resistant yellowing and blocking resistance were excellent. In particular, the cured products of Examples 11 to 15 having a high content of the condensate (A) were more excellent in heat-resistant yellowing. On the other hand, the cured products of Comparative Examples 6 and 7 were inferior in surface hardness, heat yellowing resistance, and blocking resistance because they did not contain the condensate (A). The cured products of Comparative Examples 5 and 8 did not exhibit sufficient self-healing properties because the temperature when tan δ reached the maximum exceeded 60 ° C. Further, the cured product of Comparative Example 7 did not exhibit self-healing properties because the surface was destroyed because the temperature when tan δ was maximum was less than 25 ° C.

By the phase mode of the surface observation atomic force microscope (AFM), the relative surface hardness distribution can be observed in a minute region. For the AFM observation, SPM-9600 manufactured by Shimadzu Corporation was used, and the measurement was performed in the taping mode. The probe used was SSS-NCH-10 manufactured by Toyo Corporation.

  The photograph of the AFM phase image of the coating-film surface of the laminated body (E-6) obtained in Example 16 was shown in FIG. FIG. 2 shows a photograph of the AFM phase image of the coating film surface of the laminate (e-4) obtained in Comparative Example 8. In the case of the laminated body (E-6), it was found from FIG. 1 that each region of the bright part and the dark part formed a domain with a scale of about 10 to several tens of nm. Here, the bright part corresponds to a relatively soft part and the dark part corresponds to a relatively hard part. From this, it is considered that a region rich in soft components (light portion) and a region rich in hard components (dark portion) that seems to be derived from the condensate (A) are mixed on the surface at the above length scale. It is done. It is presumed that self-healing properties were obtained by forming domains on a moderate length scale between a hard region and a soft region that can relieve the load. On the other hand, in the case of the laminate (e-4), it was found that the contrast between light and dark was small, and the areas of the bright part and the dark part were denser than the laminate (E-6). This suggests that each component is more uniformly compatibilized at the molecular level on the coating surface. Therefore, it is presumed that self-repairability could not be obtained because it is difficult to obtain a relaxation effect on the mechanical load.

The composition for surface protective coating of the present invention can effectively prevent scratches on various substrate surfaces such as home appliances, woodwork products, information equipment, electronic components, and interior and exterior of vehicles. Therefore, it can be suitably used in various industrial fields such as the home appliance field, the woodwork field, the information equipment field, the electronic component field, and the automobile field.

Claims (9)

(A) General formula (1)
R ¹ Si (OR ² ) ₃ (1)
(Wherein R ¹ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms having at least one thiol group or an aromatic hydrocarbon group having 6 to 12 carbon atoms having at least one thiol group, and R ² represents A hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.) A condensate obtained by hydrolysis and condensation of a thiol group-containing alkoxysilane (a1) represented by: and (B) a polyfunctional olefin A composition comprising
A composition for surface protective coating, wherein a temperature at which tan δ is maximized when the obtained cured product is measured by dynamic viscoelasticity at 10 Hz is in a range of 25 to 60 ° C.   The surface protection according to claim 1, wherein the condensate (A) is obtained by hydrolysis and condensation of a metal alkoxide (a2) having no thiol group together with the thiol group-containing alkoxysilane (a1). Coating composition.   The composition for surface protective coating according to claim 1 or 2, wherein the polyfunctional olefin (B) is a polyfunctional arylate and / or a polyfunctional urethane acrylate.   Furthermore, the composition for surface protection coatings in any one of Claims 1-3 containing (C) organic polyfunctional thiol compound.   The composition for surface protection coating according to claim 4, wherein the organic polyfunctional thiol compound (C) is an aliphatic ester polyfunctional thiol compound.   The use ratio of the condensate (A) is 5 to 75% by weight based on the total of 100% by weight of the condensate (A) and the polyfunctional olefin (B). 4. The composition for surface protective coatings according to 3.   The use ratio of the condensate (A) is 5 to 75% by weight based on the total 100% by weight of the condensate (A), the polyfunctional olefins (B) and the organic polyfunctional thiol compound (C). The composition for surface protective coating according to claim 4 or 5, characterized by the above.   The base material in which the surface protective layer formed by coating and hardening the composition for surface protective coatings in any one of Claims 1-7 was formed in part or all of the base-material surface. A laminate in which a substrate is plate-like and a surface protective layer formed by coating and curing the surface protective coating composition according to any one of claims 1 to 7 on one or both surfaces of the substrate. .