JPH04166272A - Method for marking car body - Google Patents

Abstract

PURPOSE:To prevent the deterioration and decrease in resistance to scuffing of a clear coating layer to be laminated on the outer surface of a sheet by using the tack-dried thermosetting sheet having a specified composition as the marking sheet. CONSTITUTION:The tack-dried thermosetting sheet consisting essentially of reactive acrylic resin, isocyanate and block isocyanate, having 50,000-1,000,000 weight average mol.wt. and -20 to 40 deg.C glass transition point and which is solid at ordinary temp. is stuck on a car body with a roller, etc., heated and cured to form a coating film. A thermosetting or photosetting clear paint is then applied on the coating film and cured.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is carried out for the purpose of improving the appearance of car bodies such as automobiles, motorcycles, and railway cars, as well as improving the surface hardness and weather resistance of car bodies. Regarding marking methods on vehicle bodies.

(Prior Art) As methods for marking the bodies of automobiles, motorcycles, etc., there are methods in which a part of the vehicle body is painted while being masked, and a method using a simple marking sheet. The former is already a known method, and the latter marking sheet, in which an adhesive is laminated on a sheet mainly made of polyvinyl chloride, has been proposed in Japanese Patent Publication No. 56-27378 and other publications.

(Problem to be solved by the invention) In the method of painting with a part of the car body masked,
The number of steps involved is large and the workability is poor, and the method of marking the car body using a marking sheet creates a level difference between the edge of the sheet and the surface of the car body, causing dust, wax, etc. on the edge of the sheet. There is a problem that it tends to accumulate and the appearance is bad. As a method to improve this problem, there is a method of attaching a marking sheet to the vehicle body and then applying a clear coating to the surface of the sheet and the vehicle body. However, in this method, since the marking sheet is made of soft vinyl chloride, there is a problem in that the clear coating layer laminated on the surface is altered by the plasticizer contained in the sheet. Further, since the marking sheet is made of a soft material, there is a problem in that the hardness of the clear coating layer portion is low and the scratch resistance is poor.

The present invention is intended to solve the above-mentioned drawbacks, and its purpose is to improve the marking force on the car body with good workability and without problems such as deterioration or scratching of the clear coating laminated on the outer surface of the seat. It is about providing law.

(Means for Solving the Problems) The method for marking a car body of the present invention has a weight average molecular weight of 50.000 to 1.000.000, a glass transition point of 20 to 40°C, and a solid state reaction at room temperature. A step of attaching a semi-cured thermosetting sheet containing a thermosetting acrylic resin, an isocyanate, and a blocked isocyanate as main components to the surface of the vehicle body, a step of heating and curing the thermosetting sheet to form a film, and a step of forming a film by heating the thermosetting sheet. The above object is achieved by applying a heat or photocurable paint to the outer surface of the curable sheet or coating and curing it.

The thermosetting sheet used in the present invention has a weight average molecular weight of so, ooo to 1.000. OOO, it is a semi-cured sheet having a glass transition point (Tg) of -20 to 40°C and mainly containing a reactive acrylic resin, isocyanate, and blocked isocyanate that are solid at room temperature.

The above-mentioned reactive acrylic resin is an acrylic resin having at least one kind of functional group such as a hydroxyl group, an amino group, or a carboxyl group. This reactive acrylic resin is, for example,
(meth)acrylic acid ester monomers having hydroxyl groups such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; such as 2-aminoethyl (meth)acrylate and 3-aminopropyl (meth)acrylate; Monomer materials selected from (meth)acrylic acid ester monomers having amine groups; and (meth)acrylic acids having carboxyl groups such as (meth)acrylic acid; generally other (meth)acrylic esters and styrene. It is obtained by polymerizing derivative monomers, maleic acid monomers, etc. using various peroxides, chain transfer agents, etc. as catalysts.

The reactive acrylic resin has a weight average molecular weight (M w
) is 50.000 to 1,000.000, preferably ioo, ooo to aoo, ooo. If the weight average molecular weight is less than 50,000, the thermosetting sheet will not be able to sufficiently follow the curved surface during application to a car body, for example, and cracks may occur. When the weight average molecular weight of the reactive acrylic resin exceeds 1,000.000, the viscosity of the solution when dissolved is too high, resulting in poor film-forming properties.

This reactive acrylic resin has a Tg (glass transition point) of - 23'C when trying to obtain a surface hardness of 8 or more (23'C) by the pencil hardness method, due to the hardness after sheet curing.
Within the range of 20 to 40°C, the functional group value (usually OH group value and NH2 value (NH2 value: calculate the amount of NH2 group added during polymerization in the same manner as the OH value, or react the NH2 group with nitrous acid) quantified by changing to OH group) and C0OH group value (quantified by changing to OH group)
COOH value: The amount of COOH groups added during polymerization is calculated in the same way as the OH value, or the value obtained by titrating COOH groups with KOH) The total value of 1 is preferably in the range of 20 to 200.

However, when trying to obtain a surface hardness that is not very high, for example, a surface hardness of 2B or less (at 23° C.) by the pencil hardness method, it is applicable even outside these ranges.

The above-mentioned blocked isocyanates are monomers or modified isocyanates having two or more isocyanate groups in the molecule, such as tolylene diisocyanate-1, diphenylmethane diisocyanate, hexamethylene diisocyanate, and inphorone diisocyanate-1. The isocyanate groups of the body are blocked (masked). In addition to phenols, block components include oximes, lactams, malonic acid esters, and the like.

This blocked isocyanate is one in which the block is removed by heating and the isocyanate group becomes active L7, which acts as a curing agent for the above-mentioned reactive acrylic resin.

The unblocked isocyanate is an isocyanate compound having two or more isocyanate groups in the molecule. For example, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, toridine diisocyanate, triphenylmethane triisocyanate, tris(isocyanate phenyl) thiophosphite, p-phenylene diisocyanate, xylylene diisocyanate, bis(isocyanate methyl)cyclohexane, dicyclo Monomers such as sylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, or trimethylolpropane adducts, isocyanurate-modified products, biuret-modified products, carbodiimide-modified products of these monomers There are various types such as urethane modified product, allophanate modified product, etc. The amount of this isocyanate added varies depending on the method of molding the sheet, but the NCO to the functional value of the reactive acrylic resin is from 1:0.1 to 1:0.1.
The amount added together with the above-mentioned pro-tsukiisocyanate is about 0.8, and the functional group value: NC0=1:0.5-2.
It is about 0.

The amount of isocyanate added is preferably the amount stated above, but in reality, in order to take into account reactivity with the reactive acrylic resin used, solvent resistance, and sheet flexibility, preliminary experiments should be conducted before sheet creation. It is preferable to decide the amount to be added.

Further, it is necessary to adjust the amount of blocked isocyanate added so that the amount of crosslinked material contained in the sheet does not increase too much depending on the amount of unblocked isocyanate added. The ratio is calculated from the above-mentioned functional group value: amount of functional group of the crosslinking agent.

Further, the thermosetting sheet may contain a coloring agent such as a pigment or dye in order to impart a decorative function.

As the coloring agent, pigments, dyes, etc. used in ordinary painting can be used. For example, pigments include titanium oxide, iron oxide, carbon black, and cyanine pigments; dyes include azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes.

Metal powders such as aluminum flakes, nickel powder, gold powder, and silver powder may also be used. Regarding the amount of colorant, when obtaining a thermosetting sheet with high hiding properties, the total amount of colorant is 2 to 2 to 100 parts by weight of the solid content of the sheet material.
A range of 400 parts by weight is preferred.

Further, the thermosetting sheet may contain a reaction control catalyst, an inorganic filler, a metal material, an anti-aging agent, a rust preventive agent, etc. for surface control, high functionality, etc. Moreover, it is possible to print on the surface of this sheet, and it is particularly preferable that the printing material is formed from such a thermosetting material.

The thermosetting sheet may be composed of a single layer (resin layer) or may be composed of multiple layers. for example,
An adhesive layer may be laminated on the back side of the sheet (the side when attached to the vehicle body). In this case, as the adhesive, a pressure-sensitive adhesive, a hot melt adhesive, or a post-curing adhesive is suitably used.

Examples of the pressure-sensitive adhesive include rubber-based, acrylic-based, urethane-based, and silicone-based adhesives. Examples of hot melt adhesives include ethylene-vinyl acetate copolymer (EVA), styrene-isoprene-styrene block copolymer (SIS), and the like. Post-curing adhesives include, for example, microcapsule-curing adhesives.

Examples of the material include uncrosslinked unsaturated polyester adhesives, uncrosslinked acrylic adhesives, and the like.

The thermosetting sheet of the present invention may be prepared by any method. When the sheet is a single layer, the following casting method is preferred.

A thermosetting resin composition made of each of the above materials is sufficiently dissolved or dispersed in an organic solvent. The resulting solution is coated onto processing paper (usually polyethylene terephthalate film or paper with a silicone-treated surface) using equipment such as a knife coater, comma coater, or reverse coater, and then dried to remove the solvent. 12 base layer (resin layer)
form. A sheet is obtained by peeling the processing paper from the base layer.

When the sheet is formed of multiple layers, it can be obtained by a casting method or a lamination method. According to the casting method, a resin layer is formed by coating a solution containing the resin composition of one of the layers onto processing paper and drying to remove the solvent.1. After that, a solution containing a composition for another resin layer is coated on this resin layer, and drying is performed to remove the solvent to form another resin layer. According to the lamination method, each layer is formed by separately applying a solution containing the resin composition of each resin layer onto process paper and drying to volatilize the solvent, and then both layers are laminated. (Heat) Press with a roll press. The thickness of the thermosetting sheet is preferably about 20 to 1.000 .mu.m when it is attached to an uneven surface of an adherend, and may be about 10 to 500 .mu.m when it is attached to a flat surface. Moreover, the thickness of the adhesive layer is preferably 10 to 100 μm.

The thermosetting resin contained in the above thermosetting paint is a commonly used commercially available transparent or light-transmitting room-temperature curing type or heat curing type such as acrylic melamine type, acrylic urethane type, fluorine type, silicone type, etc. Any type of paint can be used.

Further, as the photocurable paint, one containing a reactive vinyl monomer and/or oligomer (reactive vinyl material), a photoinitiator, a photoinitiation aid, and an oxygen polymerization inhibitor is preferably used.

Reactive vinyl materials include (meth)acrylic materials, styrene materials, and vinyl group-containing materials such as vinyl acetate. For example, (meth)acrylics include methyl (meth)acrylate, ethyl (meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, phenoxydielene glycol (meth)acrylate, etc. From the functional type, 1,6-hexadiol di(meth)acrylate, neobentyl glycol di(
meth)acrylate, polyethylene glycol di(meth)acrylate, polybrobylene glycol di(meth)acrylate
Multifunctional types such as acrylate, trimethylpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and diventaerythritol hex(meth)acrylate are applicable. In the styrene system,
Styrene, α-methylstyrene, α-ethylstyrene,
Various styrene derivatives such as p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-ethoxystyrene, p-chlorostyrene, m-chlorostyrene, and 0-chlorostyrene can be used.

Other oligomers that can be used include those having a molecular weight of 1.000 to 10.000 and having a plurality of reactive vinyl groups, such as epoxy acrylate, urethane acrylate, and polyether acrylate. These are resin PI
It can be used to lower N (-order skin irritation rate), to provide leveling, or to adjust viscosity.

In addition, monomers containing functional groups such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-aminoethyl (meth)acrylate are added to improve adhesion and flexibility. However, since these monomers generally have a high PII, the amount added is preferably 10% by weight or less based on the total amount of reactive vinyl monomers.

As the photopolymerization initiator, commonly used ones can be used.
For example, benzoin alkyl ether type, acetophenone type, benzophenone type, thioxanthone type, etc. are preferably used. Examples of benzoin ethers include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether. In the acetophenone series, 2,2-jetoxyacetophenone,
2-hydroxy-2-methylpropiophenone, p-t
er-butyltrichloroacetophenone, 2,4.6-
Examples include trimethylbenzoyldiphenylphosphine oxide. In the pentsuphenone series, benzophenone, 4
-chlorobenzophenone, 4,4-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, dibenzosuberenone and the like. Thioxanthone series include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone,
Examples include 2-ethylanthraquinone.

Among these, for hydrogen abstraction type photopolymerization initiators such as benzophenone and thioxanthone type, use n-methyljetanolamine, triethanolamine, triisopropanolamine, Michler's ketone, etc. as photoinitiation aids. are preferable, and these tertiary amines also have the effect of preventing deactivation due to oxygen. For these photoinitiators, reactive vinyl monomer 100
The range of 0.5 to 5 parts by weight is preferable, but
When improving weather resistance, it is better to use as little as possible.

Further, the number of photopolymerization initiators is not limited to one type, and two or more types may be used in combination.

The marking method on the vehicle body can be performed as shown in the following (■) or (■).

■Place the above thermosetting sheet by hand, in a vacuum, using a compressed air state, or using a roller etc. to heat it to room temperature to 150°C.
The coating is applied to a heated vehicle body (including vehicle structural members, and may be all or part of the vehicle body), and is cured by using the heat of the vehicle body and/or by further heating the sheet. Form. Thereafter, a photocurable paint is applied onto the film and cured.

(2) Paste the thermosetting sheet by hand, in a vacuum, using a compressed air state, or using a roller or the like to the vehicle body heated to room temperature to about 150°C. Thereafter, the thermosetting paint or photocurable paint is applied to the outer surface of the sheet and cured. Then, by heating, a coating is formed that hardens the sheet. When a thermosetting paint is used, the heat curing of the paint and the hardening of the sheet may be performed simultaneously.

In addition, in the above method, the paint can be applied onto the sheet by spraying with a coater or an air gun depending on the shape of the car body, and the heating temperature for thermosetting paint is preferably room temperature to 200°C. Paint light (300-5
00 nm) The irradiation dose is preferably 300 to 1000 nI11.

(Effects of the Invention) According to the method of marking a car body of the present invention, it is only necessary to attach a sheet to the car body and then paint it, so the number of steps in the painting process can be omitted. This method has the advantage that there are no problems such as deterioration of the clear coating layer or scratchiness, which is the case when marking is performed using a sheet.

(Example) The present invention will be explained below based on examples.

Note that "parts" means "parts by weight."

Husband 1 was mixed with 300 parts of ethyl acetate, reactive acrylic resin (methyl methacrylate, copolymer of methacrylic acid and 2-hydroxyethyl acrylate, Mw = 111,900, T
g = 20°C, OHHBO2C0OH value 10) as solid content, 100 parts, blocked isocyanate (manufactured by Takeda Pharmaceutical Co., Ltd., Takenate XB-72, oxime block of incyanurate of hexamethylene diisocyanate, N
GO=10.1%, solid content 70%) and 37 parts solid content (GO=10.1%, solid content 70%)
This cross-linking agent is used for the functional groups of the above-mentioned reactive acrylic resin.
0.8 equivalent of isocyanate group), isocyanate (manufactured by Nippon Polyurethane Industry ■, Coronate L, T
Trimethylolpropane adduct of DI, NC0%-13
, 2%, solid content 75%) (solid content: 7.7 parts (this crosslinking agent has 0.2 equivalents of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin) were mixed with thorough stirring. This mixture was coated with an applicator on the release surface of a polyethylene terephthalate film (hereinafter referred to as PET film) that had undergone silicone release treatment, and dried at 70°C for 10 minutes to form a semi-cured thermosetting sheet with a film thickness of 30 μm. Obtained.

A urethane pressure-sensitive adhesive sheet (thickness: 20 μm) prepared in advance was laminated onto this sheet.

The obtained thermosetting sheet was attached to a vehicle topcoat board (Cedric grade white topcoat board) with the adhesive side facing down. This was sprayed with acrylic melamine thermosetting top clear paint, and after drying at room temperature for 10 minutes,
It was heated and cured at 140'C x 20 minutes.

The hardness of the obtained coating was HB, the adhesion was 1007100 in the substrate test, and the appearance was good.

300 parts of ethyl acetate, reactive acrylic resin (methyl methacrylate, copolymer of methacrylic acid and 2-aminoethyl acrylate, M w = 182.000, Tg =
30℃, CoOH value 20 and NH2 value 40) as solid content
00 parts, blocked isocyanate (manufactured by Takeda Pharmaceutical Company Ltd.,
Takenate XB-72, isocyanate oxime block of hexamethylene diisocyanate, N G O
= 10.1%, solid content 70%) and 19 parts solid content (this crosslinking agent has 0
．． 6 equivalents of isocyanate groups), isocyanate (manufactured by Nippon Polyurethane Kogyo Co., Ltd., Corofu-) L, TDI
Trimethylolpropane adduct of, NC0%-13゜2
%, solid content 75%) (solid content: 102 parts (this crosslinking agent has 0.4 equivalent of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin) were mixed with thorough stirring. This mixture was applied to the release surface of the PET film using an applicator and dried at 70° C. for 10 minutes to obtain a semi-cured thermosetting sheet having a thickness of 30 mm.

A pre-prepared urethane adhesive sort (thickness: 20 μm) was laminated onto this sheet.

The obtained thermosetting sheet was attached to a vehicle topcoat board (Cedric grade white topcoat board) with the adhesive side facing down. After heating this at 140°C for 20 minutes to harden it,
Spray a light-curable paint (Dainippon Paint Co., Ltd., Lusen #300 Clear SC) and apply 3001 with a medium-pressure mercury lamp.
It was irradiated with 11 J and cured. - After being left at room temperature for a week, the hardness of the resulting coating was HB, and the adhesion was 1 in the substrate test.
00/100, the appearance was good.

Hidden (historic white marking sheet (Kansai Paint ■, Fandano,
A laminated adhesive layer of soft vinyl chloride) was attached to a vehicle topcoat board (Cedric grade white topcoat board) with the adhesive side facing down.

When this was sprayed with an acrylic melamine thermosetting top clear paint and dried for 10 minutes at room temperature, the marking sheet surface dissolved during drying and became wrinkled.

This was heated and cured at 140° C. for 20 minutes.

The hardness of the obtained coating was 2B, the adhesion was 1007100 in the substrate test, and the appearance was poor.

that's all

Claims (1)

[Claims] 1. Weight average molecular weight is 50,000 to 1,000,00
0. A process of attaching a semi-cured thermosetting sheet containing a reactive acrylic resin, isocyanate and block isocyanate as main components, which have a glass transition point of -20 to 40°C and are solid at room temperature, to the surface of the vehicle body; Marking on a vehicle body that includes the steps of heating and curing the thermosetting sheet to form a coating, and applying a heat or photocurable paint to the outer surface of the thermosetting sheet or the coating and curing it. Method.