JPS6036171B2 - Composition for undercoat paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an undercoat composition, in particular, a polycarbonate-based paint with excellent abrasion resistance by applying a melamine-based paint to the surface of a base material such as a polycarbonate-based plastic. This invention relates to an undercoat paint applied to produce resin molded articles.

In general, polycarbonate plastics have excellent impact resistance, but have the disadvantage that they have poor abrasion resistance and solvent resistance, are easily scratched on the surface, and are easily attacked by organic solvents. In order to compensate for this drawback, conventional methods have been used to coat the surface with various thermosetting plastics. As surface hardening coating treatment agents for plastics used for this purpose, there are melamine resins, thermosetting acrylic resins, polyester resins, polyurethane resins, etc., but none of them have sufficient adhesion to the polycarbonate base material, so these treatment agents cannot be used. Coated polycarbonate resin molded articles have had problems in terms of durability. An object of the present invention is to eliminate such conventional drawbacks and provide a resin molded article made of polycarbonate or the like having improved abrasion resistance, durability, and solvent resistance. The present inventor has created a layer of a substance that has good adhesion to both polycarbonate resin and melamine resin between the base material of a polycarbonate resin molded article and the melamine resin coating layer coated thereon. By interposing it, the adhesion of the melamine-based resin coating layer to the base material was improved, and therefore the abrasion resistance and solvent resistance of the polycarbonate resin molded article were improved.

That is, the present invention provides an acrylic compound having a hydroxyl group, an amino group derivative,
The main component is a mixture of an acrylic compound having an epoxy group or a furyl group in a weight ratio of 95:5 to 5:95, which is polymerized or copolymerized to have a molecular weight of 5,000 to 50,000. , an undercoat composition for producing wear-resistant coated resin articles.

In the present invention, the hydroxyl groups in the composition used as an undercoat layer interposed between the molded article made of polycarbonate resin or the like as a base material and the top coat layer of resin such as melamine resin are The amino group derivative, epoxy group, or furyl group in the product each has high reactivity with the polycarbonate resin base material. When this undercoat composition is coated on the surface of a polycarbonate resin molded article and subjected to polymerization treatment or drying, the amino group derivative, epoxy group, or furyl group acts on the polycarbonate resin, so that the undercoat layer is coated on the polycarbonate resin. It shows great adhesion to. Also, when a melamine resin topcoat is coated on top of this undercoat layer and cured, the hydroxyl groups in the undercoat react with the methylol groups in the melamine resin, so that the melamine resin topcoat after curing is Shows great adhesion to undercoat layers.
As a result, the melamine resin coating layer strongly adheres to the polycarbonate resin substrate, thereby improving the abrasion resistance and solvent resistance of the polycarbonate resin molded article. The acrylic compound having a hydroxyl group used in the present invention includes an ester of an unsaturated fatty acid represented by the general formula, where R is hydrogen or a methyl group, and R2 is an alkyl group having a hydroxyl group.

For example, if R,=day, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1
, 4, butylene glycol monoacrylate.

When R,=CH3, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 1,4,butylene glycol monomethacrylate, hydroxyallyl methacrylate, polypropylene glycol monomethacrylate, glycerin.

One example is monomethacrylate. In addition, as an acrylic compound having an amino group derivative, for example, if R, of an unsaturated fatty acid ester represented by the general formula has hydrogen and a methyl group, and the ester residue R2 has an amino group derivative, for example, R, = day. 2-N,N-dimethylaminoethyl acrylate, 2-
N,N diethylaminoethyl acrylate, 2-N,N
-dibutylaminoethyl acrylate, 3-N,N diethylaminof.

Lopylacrylate, 2-N,N dibutylaminop.

Pyracrylate, 3-N,N dibutylaminopropyl acrylate, 2-N,N-dimethylaminoethyl methacrylate when R,=CH3, 2
-N,N diethylaminoethyl methacrylate, 2-N
,N dibutylaminoethyl methacrylate, 3-N,N
Diethylaminopropyl methacrylate, 2-N,N dibutylaminopropyl methacrylate, and acrylamide substituted products of the general formula in which R is replaced with hydrogen and a methyl group, and R2R3 is replaced with hydrogen and an alkyl group, such as R, = day In the case of N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N
-butylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-dibutylacrylamide.

In the case of R,=CH3, N-methylmethacrylamide, N-ethylmethacrylamide, N-rt-butylmethacrylamide, NN-diethylmethacrylamide, N,N-dipropylmethacrylamide, NN-dibutylmethacrylamide, and other derivatives such as N-methylolacrylamide,
Examples include N-butoxymethylamide, N-isobutoxymethylacrylamide, and diacetone acrylamide.

Examples of the acrylic compound having an epoxy group include glycidyl acrylate and glycidyl methacrylate.

Examples of the acrylic compound having a furyl group include tetrahydrofurfuryl acrylate and tetrahydrofurfuryl methacrylate.

If the ratio of acrylic compound (1) and The weight ratio of both acrylic compounds (2) should be 95:5 to 5:95, since this will weaken the adhesion and worsen the overall adhesion.
The ratio is preferably within the range of 80:20 to 20:80.

Each acrylic compound is not limited to one type, but may be a mixture of two or more types, and the mixing weight ratio of both acrylic compounds is expressed by the total weight of the mixture of each acrylic compound. If the hardness of the undercoat layer after baking is too small, sufficient adhesion cannot be obtained.

Furthermore, since the strength of the undercoat layer itself is not very high, if the thickness is too large, damage will easily occur inside the undercoat layer when external force is applied to the topcoat layer, resulting in weakening of the adhesive force of the topcoat layer. Therefore, the thickness of the undercoat layer is 0.
It is preferably within the range of 1 to 3 Buddhas, particularly preferably within the range of 0.5 to 1.0 Buddhas.

Polycarbonate-based resin molded articles with improved abrasion resistance can be obtained by combining 'a} a vinyl compound having a carboxyl group or an amino group, or (b} an acrylic compound having a hydroxyl group, with an amino group derivative, an epoxy group, or a furyl group). Weight ratio of acrylic compound: 95:5 to 5:
A mixture in a ratio of 95 to 95, with addition of an initiating catalyst, a diluent, and optionally a crosslinking agent and a crosslinking catalyst, or a polymer of the vinyl compound {a} or a copolymer of the mixture tb} The surface of a polycarbonate resin molded article is coated with a diluent and optionally a crosslinking agent and a crosslinking catalyst, and then the coating is dried to scatter the diluent, or the resin molded article is It is manufactured by baking and polymerizing (polymerizing and crosslinking if a crosslinking agent is added) by baking at a high temperature below the heat distortion temperature of , and then coating it with a melamine resin paint and baking.

The above-mentioned vinyl compound (a) and mixture (
b}, rather than using a polymerization catalyst and a diluent added to either one of the vinyl compound {a) and a copolymer of the mixture {b') to which a diluent is added. is preferable.

This is because when used in the form of a polymer, there is no need for a polymerization reaction in a non-oxidizing atmosphere, the uniformity of the undercoat film is improved, and the degree of polymerization can be adjusted to select an appropriate molecular weight. This has the advantage that it is possible to obtain a coating material with an appropriate viscosity according to various coating methods, and therefore a smooth coating film with a uniform thickness can be easily obtained. In the present invention, these acrylic compound monomers or monomer mixtures are used as polymerization initiators such as MBN, ammonium peroxide,
Polymerization (including copolymerization) or polymerization (including copolymerization) is carried out in the presence of a catalyst known for use in the polymerization of acrylic compounds, such as awamonium persulfate, and in a non-oxidizing atmosphere.

The preferred molecular weight range of the polymer is from 5,000 to 50,000, which means that even if the polymerization is completed, there will be no residual polymerization (
(including a preliminary copolymer). Next, an undercoat paint is applied to the surface of the resin molded article, such as polycarbonate, by a conventional coating method such as a dipping method, a spraying method, a low-foo coating method, or a flow coating method. After application,
The undercoat film is baked.

Although the baking temperature varies depending on the composition of the undercoat used, it is generally effective to heat and cure at a temperature of at least 5,000 ℃. The upper limit of the dawning temperature is the heat deformation temperature of the polycarbonate resin base material (usually 110 to 13
000). When a mixture {b}' with a polymerization catalyst, a diluent and, if necessary, a crosslinking agent and a crosslinking catalyst are used as an undercoat, and a mixture {b}' with a diluent, a crosslinking agent and a crosslinking agent added to the co-vertical In the case of using an agent to which an agent has been added, polymerization and crosslinking are completed by baking the undercoat film.

However, when using the copolymer of mixture {b) with only a diluent added without adding a crosslinking agent or crosslinking catalyst as an undercoat, baking of the undercoat is not essential, and this paint is dried. Simply let the diluent evaporate. Baking can generally be carried out in a heated furnace, preferably at a temperature in the range of 100 to 130 degrees
The undercoat film is baked and cured by heat treatment for a minute to three hours.

When using mixture 'b}' with a polymerization catalyst, diluent, and optionally a crosslinking agent and crosslinking catalyst added as an undercoat, polymerization of the undercoat film (or polymerization when a crosslinking agent is added) is required. and crosslinking) is carried out by competition in a non-oxidizing atmosphere. On the other hand, if the copolymer of mixture 'b) plus a diluent, a crosslinking agent and a crosslinking catalyst is used as an undercoat, the crosslinking of the undercoat is carried out by baking in an air atmosphere. When using an undercoat paint in which a polymerization initiating catalyst, a diluent, and, if necessary, a crosslinking agent and a crosslinking catalyst are added to the precopolymer mixture (b), it is necessary to Completion of polymerization and crosslinking in some cases) is carried out by baking in a non-oxidizing atmosphere.
When using an undercoat paint containing a diluent added to the copolymer (b), there is no need to apply bran to the undercoat film; just dry it so that the diluent evaporates, and the undercoat film becomes a hard, heavy layer. Form a membrane of coalescence. Next, apply resin paint such as melamine,
The undercoat film is applied to the surface of the baked polycarbonate resin molded article by a normal coating method, and then the base coat is applied at a temperature below the heat distortion temperature of the polycarbonate resin base material.
For example, within the temperature range of 10,000 to 16,000
The top coat of the melamine resin paint is baked and cured by heat treatment for a minute to five hours.

The thickness of the top coat after curing is usually 3 to 50 mm, more preferably 5 to 20 mm. Instead of baking the basecoat and topcoat separately in this way, the applied basecoat is dried at or near room temperature to release the diluent, and then a melamine resin topcoat is applied over it. The undercoat film and the topcoat film may be cured by baking at the same time by applying and heat-treating.

Examples of diluents used in the present invention include methanol, ethanol, and isof.

Alcohols such as ro/f-nol and n-butanol; Ethers such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and cellosol acetate; ketones such as methyl ethyl ketone and methyl propyl ketone; methyl acetate, ethyl acetate, propyl acetate, isop acetate;

A single or mixed solvent of esters such as pill and butyl acetate is desirable. It is not necessary to add a crosslinking agent to the undercoat used in the present invention.

However, when the topcoat is applied, the organic solvent in the topcoat may erode the undercoat, resulting in a decrease in the adhesion of the topcoat. Preferably, a crosslinking agent is added to the paint. The usual amount of crosslinking agent added is from 0.05 to 0.05 per equivalent of the relevant functional group (carboxyl group, etc.) of the acrylic compound, mixture thereof or polymer thereof used.
7 equivalents, more preferably 0.2 to 0.4 equivalents. Examples of the crosslinking agent include ethylene glycol dimethacrylate, ethylene glycol diacrylate, divinylbenzene, divinyltoluene, triallylmelamine, alkyl etherified methylolmelamine, N,N'-
Methylene bisacrylamide, glycerin trimethacrylate, diallyl maleate, divinyl ether, diallyl monoethylene glycol citrate, allyl vinyl maleate, ethylene glycol vinyl allyl citrate, diallyl itaconate, ethylene glycol gester of itaconic acid, propylene glycol divinyl ether methacrylate, propylene glycol diacrylate, divinyl sulfone, hexahydro-1,3,5-triacryltriazine, triallylphosphite, diaryl ester of benzenesulfonic acid, polyester of maleic anhydride and triethylene glycol, diethylene glycol diacrylate, Polyallyl sucrose, polyallyl glycose such as diallyl sucrose and triallyl glycose, sucrose diacrylate, glycosyl dimethacrylate, bentaerythritol diacrylate, sorbitol dimethacrylate, etc. can be used.

Crosslinking catalysts used with crosslinking agents include hydrochloric acid, ammonium chloride, ammonium nitrate, ammonium thiocyanate, etc. In addition, if necessary, commercially available flow control agents to obtain a smooth coating film, such as FC-431 (trade name) manufactured by Mining and Manufacturing Company was added to form an undercoat paint.

Examples of the polycarbonate resin in the present invention include 4,4'-isopropylidene diphenol polycarbonate and US Pat.
It refers to other polycarbonates, diethylene glycol bisallyl carbonate, etc., described in pages 176 to 176 (published by Shin, 1962). The melamine-based resin paint used in the present invention is generally available and has alkyl etherified methylol melamine as its main component, such as alkyl etherified methylol melamine and hydrochloric acid or di- and trimethylol melamine as a catalyst. A self-condensing melamine paint with added salt can be used.

However, a preferable melamine resin paint is
421 and Hakamasho No. 49-46788, namely {a] methylolmelamine having 3 to 6 methylol groups, at least a part of which may be alkyl etherified; (b}
A chain or alicyclic compound having at least two functional groups selected from the group consisting of a hydroxyl group, an amino group and a carboxyl group, especially the methylol of 1,3-propanediol, 1,4-butanediol, or 1,8-octanediol 0.1 to 1.5 equivalents, especially 0.1 to 1.5 equivalents per equivalent of melamine.
This is a surface-curing coating composition containing a mixture of 8 to 12 equivalents and/or a precondensate of the above-mentioned component axis and component 'b' as a curable component. Examples of the present invention will be described below. Example: After filling a three-necked flask with nitrogen, equipped with a thermometer, a nitrogen inlet tube, and adding ethyl cellosolve for 320 minutes, 2 hours.
-Hydroxyethyl methacrylate 36 days, dimethylaminoethyl methacrylate 44 days and Yama BNO. The temperature is raised to 90 degrees Celsius for four evenings while quietly worshiping the lights.

The process continues for about 4 hours while constantly blowing nitrogen. The mixture in the flask becomes a pale yellow transparent liquid with a viscosity of about 10 P, and a copolymer of 2-hydroxyethyl methacrylate and dimethylaminoethyl methacrylate is formed. Take this liquid out of the flask for 100 minutes, add 0.4 hours of xamethoxymethyl melamine, 0.057 hours of ammonium chloride, 900 hours of ethyl cellosolve, and a little flow control agent, and add 100 minutes of this liquid to the skin of 2 times thick, which has been washed in advance. It was coated on a polycarbonate plate by the bonding method and heat treated in a heating furnace for 130 minutes to harden the undercoat film. 65 parts of hexakismethoxymethylol melamine and 50.5 parts of 14-butanediol are reacted to obtain a prepolymer with a molecular weight of 500, and 1 part of ethylene glycol is added to the prepolymer to form 40 parts of ethyl ester. A melamine-based resin paint obtained by dissolving in cellosolve and adding paratoluene sulfonic acid as a catalyst was applied in the same manner on the undercoat film.
As a result of baking at 0 for 40 minutes, a coating film with good abrasion resistance, adhesion, and weather resistance was obtained as shown below.

A sample of a polycarbonate plate having this undercoat film and a topcoat film thereon was compared with a sample of a polycarbonate board without coating treatment, and a sample of a polycarbonate board coated only with the above-mentioned topcoat film without coating the above-mentioned undercoat film. For comparison, performance test results of pencil hardness (JISK-5400), adhesion, thermal shock resistance, weather resistance, water resistance, and solvent resistance are shown in Tables 1 and 2. The adhesion was determined by a so-called cross-cut tape test, in which 11 parallel lines were drawn vertically and horizontally with a knife on the surface of each sample at 1-leg intervals to cross-cut ION solid squares, and then After attaching cellophane tape to the surface, the tape is peeled off, and the number of squares peeled off among the 100 squares of the coating film is displayed. Thermal shock resistance was 8000 after holding each sample at -30q○ for 16 hours.
Hold for 8 hours and repeat this several times to form a coating (
The number of repetitions until peeling occurs (or sample surface) is indicated. Weather resistance is expressed as the time until abnormalities occur in the coating film (or surface) after processing with a weather meter. Water resistance is indicated by the presence or absence of surface abnormalities after each sample is boiled for 3 hours. Solvent resistance is expressed as the time required for each sample to be immersed in each solvent at each concentration until abnormalities appear on the surface. Table 1 Table 2 Example 2 In a three-necked flask in the same manner as in Example 1, 320 g of ethyl cellosolve and 3 g of 2-hydroxyethyl methacrylate were added.
8 evenings, glycidyl methacrylate 42 evenings, Yama BNO. 4
The temperature was raised to 8,000 ℃ in a nitrogen atmosphere, and the heating was continued for 4 hours.

The mixture in the flask reacts to become a clear liquid with a viscosity of 10 P, forming a copolymer of 2-hydroxyethyl methacrylate and glycidyl methacrylate. This liquid was taken out from the flask for 100 minutes, and 0.43 tons of xamethoxymethylmelamine was added as a catalyst, and 0.43 tons of ammonium chloride was added as a catalyst.
069, diluted with 900 ml of ethyl cellosolve, added a small amount of flow control agent, applied to a pre-washed polycarbonate board with a thickness of 2/2 by the bonding method, and heat-treated in a heating furnace for 1300050 minutes. The film is competitively cured. Furthermore, a plastic surface hardening coating obtained by reacting hexamethoxymethylmelamine with 1,4-butanediol was applied in the same manner.
As a result of baking at 0oC for 40 minutes, a coating film with good abrasion resistance, adhesion, and weather resistance was obtained.

Example 3 In a three-necked flask in the same manner as in Example 1, 220 ml of ethyl cellosolve, 100 ml of water, 51.7 ml of 2-hydroxyethyl methacrylate, 28.3 ml of acrylamide,
AIBNO. Add 4 nights and raise the temperature to 8000 in a nitrogen atmosphere.
Raise the temperature to 6 hours and continue to use Tana Azusa for 6 hours.

The mixture in the flask reacts to form a milky white liquid with a viscosity of 24 mm and a copolymer of 2-hydroxyethyl methacrylate and acrylamide. Take out this liquid from the flask, add 0.58 g of toxymethyl melamine, 0.08 g of ammonium chloride as a catalyst, dilute with 675 g of ethyl cellosolve, and 225 g of water, add an appropriate flow control agent, and wash beforehand. It is coated on a polycarbonate plate with a certain thickness of 2 m/skin by the bonding method and heat treated in a heating furnace at 130 qo for 50 minutes to bake and harden the coating film.

Furthermore, on top of that, hexamethylol melamine 65 and 1.4
A plastic surface hardening coating obtained by reacting with butanediol 1509 was applied in the same manner as 120002.
As a result of competing over time, a coating film with good abrasion resistance, adhesion, and weather resistance was obtained.

Example 4 In the same manner as in Example 1, 320 ml of ethyl cellosolve and 4 ml of 2-hydroxyethyl mecrylate were added to a three-necked flask.
5 nights, N-methylol acrylamide 35 nights, MBN
O. After 4 nights, the temperature was raised to 8,000 in a nitrogen atmosphere, and the pestle was continued for 6 hours.

The mixture in the flask reacts to form an opalescent, opaque liquid with a viscosity of 25 mm and a copolymer of 2-hydroxyethyl methacrylate and N-methylolacrylamide. This liquid was taken out from the flask for 100 minutes, and a flow control agent was added to 900 minutes of ethyl cellosolve as a diluent with 0.51 toxymethyl melamine as a catalyst and 0.07 ammonium chloride as a diluent. The coating film was applied to a polycarbonate plate of 50 mm by dipping method, and then heat treated in a heating furnace at 130°C for 50 minutes to harden the coating film.

Furthermore, on top of that, hexamethylol melamine 65 and 1.4
A coating for plastic surface hardening treatment obtained by reacting 150 g of butanediol was applied in the same manner and heated to 130°C for 2 hours.
As a result of time baking, a coating film with good abrasion resistance, adhesion, and weather resistance was obtained. Example 5 Using the same method as in Example 1, 50 ml of acrylamide, 200 ml of water, and 0.50 ml of ammonium persulfate were placed in a three-necked flask.
The temperature is raised to 80 qo and continued for 2 hours while adding evening water and praying quietly.

The mixture in the flask becomes a transparent liquid with a viscosity of 20 and about P, and an acrylamide polymer is formed. Take out this liquid from the flask and add 2.0 g of xamethoxymethyl melamine and 0.0 g of ammonium chloride as a catalyst.
Added 08 evening, Ethilce.

Diluted with Solf 300ml and Water 600ml, added flow control agent appropriately, and pre-rinsed to a thickness of 2 pieces/
The kite was applied to a polycarbonate plate by dipping and heat-treated in a heating oven for 1,300,050 minutes to competitively cure the coating. Furthermore, a melamine modified to have self-condensing properties, such as trimethylol, trimethoxymethylmethylmelamine, and a suitable catalyst added to form a paint for plastic surface hardening, was applied on top of the coating. As shown in Tables 1 and 2, a coating film with good adhesion and weather resistance was obtained after soaking for 40 minutes.

Example 6 In a three-necked flask in the same manner as in Example 1, 360 g of ethyl cellosolve and 4 g of 2-hydroxyethyl methacrylate were added.
0ta yen tetrahydrofurfuryl methacrylate 529,
AIBNO. Add 45 days of heat to a temperature of 8,000 in a nitrogen atmosphere.
Raise the temperature to 100% and continue to let it rise for 2 hours.

Then, the mixture in the flask reacts and becomes transparent with a viscosity of 6$,
The liquid becomes a liquid of about P, and a copolymer of 2-hydroxyethyl methacrylate and tetrahydrofurfuryl methacrylate is formed. This liquid was taken out from the flask for 100 minutes, and hexamethoxymethylmelamine was taken out for 0.4 hours.
Add 0.06 mm of ammonium chloride as a catalyst, dilute 900 mm of ethyl cellosolve, add a small amount of flow control agent, and apply by dipping method onto a pre-washed polycarbonate plate with a thickness of 2 mm. 13 in the heating furnace
Heat treatment is performed for 5 minutes at 0oC to bake and harden the coating film. Furthermore, a plastic surface hardening coating containing triethoxymelamine and di- and trimethylolmelamine hydrochloride as main components was applied in the same manner, and
As a result of the splitting, a coating film with good abrasion resistance, adhesion properties, and weather resistance was obtained.

Example 7 In a three-necked flask in the same manner as in Example 1, 230 g of ethyl cellosolve, 100 g of water, 50 g of tetrahydrofurfuryl methacrylate, 20 g of acrylamide, and AIB were added.
NO. Add 35 minutes of heat and raise the temperature to 90oC while praying for 4 hours.

The mixture in the flask reacts to become a clear liquid with a viscosity of 10 mm and a copolymer of tetrahydrofurfuryl methacrylate and acrylamide. This liquid was taken out from the flask for 100 minutes, 1.36 hours of hexamethoxymethylmelamine, and 0.0 hours of ammonium chloride as a catalyst.
Add 20 parts of the mixture, dilute with 675 parts of ethyl cellosolve, and 225 parts of water, add a flow control agent appropriately, and apply it to a pre-washed 2-thickness polycarbonate board by dipping method. The coating film is baked and cured by heat treatment at 130° C. for 50 minutes in a heating furnace.

Claims (1)

[Claims] 1. An acrylic compound having a hydroxyl group and an acrylic compound having an amino group derivative, an epoxy group, or a furyl group in a weight ratio of 95:5 to 5:95.
A mixture with a molecular weight of 5000 to 5000
An undercoat composition for producing abrasion-resistant coated resin articles, the main component of which is polymerized or copolymerized so as to be 0.