AU607317B2 - Two-pack acryl-urethane coating material - Google Patents

Description

TO: The Commissioner of Patents, COMMONWEALTH OF AUSTRALIA APPLCATION, ACCEPTED AND

AMENDMENTS

LC c ii

_L_

COMMONWEALTH OF AUSTRALIA Patent Act 1952 6073 1 COMPLETE SPECI FICATION

(ORIGINAL)

Class Int. Class Application Number Lodged 04 4.

Complete Specification Lodged Accepted Published Priority: 28 March 1988 Related Art Name of Applicant Address of Applicant TOAGOSEI CHEMICAL INDUSTRY CO., LTD.

14-1, Nishi Shimbashi, 1-chome, Minato-ku, Tokyo, Japan '0 0 Actual Inventor Kazuko MURAI, Akio OTERA, Address for Service F.B. RICE CO., Patent Attorneys, 28A Montague Street, BALMAIN. 2041.

Complete Specification for the invention entitled: "TWO-PACK ACRYL-URETHANE COATING MATERIAL" The following statement is a full description of this invention including the best method of performing it known to Us:rl i t 0 on 0004 oP 0 0 00 00 t o 6 0 o 6 0066 06) 0 ,r 0 0s o pa 6000 6 6( 0 6 I 1 This invention relates to a two-pack acrylurethane coating material used for coating automobiles, construction materials, domestic electric instruments, etc. More particularly, this invention relates to a two-pack acryl-urethane coating material comprising an acrylic graft polymer as a main ingredient and a polyisocyanate compound as a crosslinking agent.

A two-pack acryl-urethane coating material is usually constituted of an acrylic elastomer having 10 hydroxyl groups the so-called acryl-polyol) and a yellowing-proof polyisocyanate compound. When coated by spraying, for example, it exhibits excellent buildup maintenance, gloss and coating film durability ar, is widely used as an overcoating material of light automo- 15 biles soft motor bicycle and the like), automobiles, construction materials, domestic electric instruments, etc.

However, the prior two-pack acryl-urethane coating material has been disadvantageous in that its drying takes a long period of time at elevated temperature and its color control is troublesome because of its poor pigment dispersibility. In order to improve its drying property, it has recently been proposed to use, as the acryl-polyol, a graft polymer prepared by grafting a side.chain of alkyl acrylate or the like onto cellulose lai 1 acetate-butyrate (hereinafter, abbreviated to CAB).

However, this technique is not yet on the satisfactory level, that is, it is accompanied by new disadvantages that wather resistance is deteriorated and, when the coating material is used for repair, the solvent used for dissolving CAB, such as a ketone compound and the like, sometimes injures the undercoating due to its high dissolving power.

It is the object of this invention to provide 10 a two-pack acryl-urethane coating material excellent in o0 0o Soo drying property owing to the presence of isocyanate group o 0 0 of which crosslinking reaction can be completed in a o short period of time.

O

O

With the aim of solving the above-mentioned 0 o 15 problems, the present inventors conducted many studies, o0 o as the result of which this invention has been accomplished.

0 .Thus, this invention provides a two-pack acryl- 0 0. 0% urethane coating material comprising: a graft polymer having in its molecule a 00 0 S oo 20 functional group reactive with isocyanate group obtained by radical-copolymerizing a macromonomer having a number average molecular weight of 1,000 to 20,000 and (meth)acryloyl group on its one molecular end and containing by weight or more, based on the total weight of total monomer units, of a monomer unit derived from a monomer represented by the following general formula:

CH

CH2

CR

1

R

2 2

'I

1 wherein R 1 represents H or CH 3 and R 2 represents phenyl group, nitrile group or group -COOR 3

(R

3 is a saturated aliphatic or alicyclic hydrocarbon group having 1 to carbon atoms) with an alkyl (meth)acrylate or with an alkyl (meth)acrylate and another monomer copolymerizable with it; and (ii) a polyisocyanate compound.

Now, this invention will be illustrated below in more detail.

10 The macromonomer used as a starting material for the production of the graft polymer of this invention is a polymer comprising at least 75% by weight, based on the total weight of the total monomer units, of a monomer unit derived from a monomer represented by the following 15 general formula: 0 0 0 0 o of 000 o a t o 0 0 0 0 0 0 4 0 0

CH

2 CR R 2 wherein R 1 represents H or CH 3 and R2 represents phenyl group, nitrile group or group -COOR 3

(R

3 is a saturated aliphatic or alicyclic hydrocarbon group having 1 to carbon atoms). It is a macromonomer having a number average molecular weight of 1,000 to 20,000 and a (meth)acryloyl group on its one molecular end.

Concrete examples of the monomer represented by the above-mentioned general formula CH 2

CR

1

R

2 include the followings: aromatic vinyl compounds such as styrene, a-methylstyrene and the like; cyano-vinyl compounds such 3 i l u -L i.

''Z

o i 0 00 0 o o o ons 00 '4 0 Q D 00 0 0 '40n 0 0 0 0 '4 S I 0 o 0 g 0 o 0 00 co a o e o 0^0 0 0 &0f 0 0 00 0 o a o o 0 0 00 6 0 04 BD 1 as acrylonitrile, methacrylonitrile and the like; methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and the like; and acrylic esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate and the like. These monomers may be used either alone or in combination of two or more members.

10 Apart from the monomers represented by the general formula CH 2

CR

1

R

2 wherein R 1 represents H or

CH

3 and R 2 represents phenyl group, nitrile group or

-COOR

3

(R

3 is a saturated aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms), the following 15 monomers can also be cited as monomers capable of participating in the formation of said macromonomer: vinyl carboxylates such as vinyl acetate and the like; vinyl ethers such as vinyl propyl ether, vinyl butyl ether and the like; (meth)acrylic esters such as 2- 20 hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, polyethylene glycol mono(meth)acrylate and the like (hereinafter, they are generically referred to as "hydroxyl group-containing (meth)acrylic esters"); aminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate and the like; maleic anhydride; and the like. The content of the monomer unit derived from these monomers must be lower than 25% by weight. If its content is not lower

:I

I

r

I

4 i. _I il LC i ri 0 0 0 0 0 0 0 00 o 0 0 O 00 00 00 o0 o0 oA a 0 0, 0 0 4 4 00 4 0 0 1 <t a i 1 than 25% by weight, the content of the monomer unit derived from the monomer represented by general formula

CH

2

CR

1

R

2 cannot reach 75% by weight or more and therefore the resulting coating material is not good in gloss and water resistance.

As will be mentioned later in this specification, the graft polymer of this invention must have, in its molecule, a functional group reactive with isocyanate group, such as hydroxyl group, carboxyl group, amino I I 10 group or a group of the formula: C C 0 0 0 Accordingly, when the radical-polymerizable monomer to be radical-copolymerized with the macromonomer contains no monomer having a functional group reactive with isocyanate group, it is recommendable to use, as the 15 macromonomer, a functional group-containing macromonomer prepared by using a monomer comprising a hydroxyl groupcontaining (meth)acrylic ester, aminoalkyl (meth)acrylate, maleic anhydride or the like.

Next, the synthesis of the macromonomer will be described briefly.

The above-mentioned monomer or monomer mixture is polymerized at a temperature of about 60 to 90 0 C for about 4 to 12 hours in an organic solvent by the use of an azo type polymerization initiator such as 2,2'azobisisobutyronitrile, 4,4'-azobis-4-cyanovaleric acid or the like in the presence of a chain transfer agent of which use in the production of a macromonomer has 5 _:aw i 0 00 o o o 0 00 o o o o 0 0 0. 00 00 0 000 0 0 01 00 00 0 0 0 0 0 0 0 00 0 0 o a0 0 0 t 1 already been known, for example, a mercaptan compound having a carboxyl or other functional group such as mercaptoacetic acid or the like to form a polymer having a number average molecular weight of 1,000 to 20,000 and a carboxyl or other functional group on its molecular end. Then, the polymer thus obtained is reacted with a compound having both a group reactive with the abovementioned carboxyl or other functional group epoxy group) and a methacryloyl or acryloyl group, such as 10 glycidyl methacrylate, glycidyl acrylate or the like, at a reaction temperature of 80 to 90 0 C in the presence of an amine type catalyst, whereby a macromonomer having (meth)acryloyl group on its one molecular end can be synthesized.

The term "number average molecular weight" referred to in this invention means a number average molecular weight calculated as that of polystyrene which has been measured by gel permeation chromatography (hereinafter, referred to as GPC).

20 Next, the graft polymer of this invention will be explained.

The graft polymer of this invention is a graft polymer having a .functional group reactive with isocyanate group in its molecule, which can be obtained by radicalcopolymerizing the above-mentioned macromonomer with an alkyi (meth)acrylate or with an alkyl (meth)acrylate and another monomer copolymerizable with it.

As mentioned above, said functional group 6 4 O O o o0 o o o o 0.

0 0 0o 0 4 0 1 reactive with isocyanate group is a functional group such as hydroxyl group, carboxyl group, amino group, I I the group C C or the like.

0 0 0 As said alkyl (meth)acrylate, the alkyl methacrylate and alkyl acrylate which have been mentioned above as a starting compound for the macromonomer can be used. As said "another monomer" copolymerizable with such an alkyl (meth)acrylate, the followings can be cited: styrene, a-methylstyrene, acrylonitrile, meth- 10 acrylonitrile, vinyl chloride, vinyl acetate, N-methylolacrylamide, acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, itaconic acid, maleic anhydride, and the like.

When "another monomer" copolymerizable with an alkyl (meth)acrylate is used in combination with the alkyl (meth)acrylate, it is preferable to use the alkyl (meth)acrylate in an amount of 50% by weight or more based on the total amount of the alkyi (meth)acrylate and "another monomer".

Said alkyl (meth)acrylate may be either a single compound or a combination of two or more alkyl (meth)acrylates. Similarly, said "another monomer" 7 4.i i ~1 L _i_-li-L 1 may also be either a single compound or a combination of two or more other monomers.

When a macromonomer having no functional group reactive with isocyanate group is used as the macromonomer of this invention, the monomer to be radical-copolymerized with the macromonomer should be selected from monomer mixtures comprising carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic anhydride and the like; hydroxyl group-containing monomers such as 10 2-hydroxyethyl (meth)acrylate and the like; and amino O 00 group-containing monomers such as dimethylaminoethyl 0 0 0 o 0 (meth)acrylate and the like in order to introduce a functional group reactive with isocyanate group into the graft polymer. Needless to say, such a monomer having .15 a functional group reactive with isocyanate group may be used for producing the graft polymer also when the macromonomer itself has a functional group reactive with isocyanate group.

Preferably, the content of the monomer unit Sooo 20 having a functional group reactive with isocyanate group o" °in the graft polymer is 0.1 to 20% by weight based on the summed weight of total monomer units. If the content is smaller than 0.1% by weight, no sufficient li crosslinkage can be formed by the reaction with a polyisocyanate compound, so that hardness and solvent resistance of the coating film are inferior. If the content exceeds 20% by weight, the relative contents, in the graft polymer, of the monomer unit derived from ;e 1 the monomer represented by the general formula, CH 2 CR R 2 alkyl (meth)acrylate and the like) and the monomer unit derived from "another monomer" optionally used in combination with it become lower, and therefore the resulting coating film is apt to be inferior in gloss, weather resistance and water resistance.

SIn radical-copolymerizing the macromonomer with the alkyl (meth)acrylate or with the alkyl (meth)acrylate and other monomer copolymerizable with it, the a n 10 polymerization reaction may be carried out in the Sn presence of CAB. In this case, there is formed a polymer mixture comprising a graft polymer formed from the o° macromonomer and a graft polymer formed by the graft polymerization of the monomer onto CAB. Such a polymer 15 mixture can also be used as a graft polymer of this 0 0 0 'o0 invention.

O As the polymerization process for obtaining a 0 the graft polymer, the conventional solution polymerization process, suspension polymerization process, bulk S a polymerization process, emulsion polymerization process and the like can be adopted. In adopting any of these processes, the polymerization can be carried out in the usual way.

The graft polymer obtained by the abovementioned polymerization processes can be formed into a coating material by dissolving it into an organic solvent such as butyl acetate, toluene, xylene or the like and then adding thereto additives for coating materials such 9

LYL--~IL~~

1 as pigment, levelling agent and the like. As said pigment, titanium dioxide, Phthalocyanine Blue and Green, oxides and sulfides of metals, metallic flakes such as aluminum flake, and the like can be used. Usually, the pigment is used in an amount sufficient to adjust the total solid concentration of the resulting coating material at about 30 to 80% by weight.

To the solution of the graft polymer in an organic solvent, to the main ingredient of a twopack acryl-urethane coating material, an appropriate o oamount of the conventional acryl-polyol or the like may be added, if it is desired. In the main ingredient, the o content of the graft polymer or the resin component consisting of the graft polymer and the acryl-polyol may be comparable to that in the main ingredient of the °a prior two-pack acryl-urethane coating materials.

c t The graft polymer of the present invention is a graft polymer comprising a graft component orginated Sfrom the macromonomer and a trunk component consisting o 20 of a polymer constituted of monomer units which have been copolymerized with the macromonomer, and the graft component is well controlled in the degree of polymerization and content. Since the present two-pack acrylurethane coating material comprises such a graft polymer having the above-mentioned characteristic features as its main ingredient, these characteristic features are exhibited on the surface and inside of the resulting coating film, as the result of which the acryl-urethane 10 -e r .L -lr .r 00 0 0 0 0 0004 4 4 on o o0 o 0 01 0 0 o o 0n 00 4B o I 4 1 coating material of this invention has the following useful properties.

That is, when used as a repair coating material for automobiles, it exhibits an excellent rapid-drying property and an excellent gloss and does not injure the undercoating with the solvent which it contains. When used as an overcoating for construction materials, it exhibits an improved weather resistance, an excellent adaptability to the environmental change of a substrate and a high hardness. When used as a coating material for the bodies of scooter, motor bicycle and the like, it exhibits an excellent adhesion to various plastic materials.

Next, the polyisocyanate compound to be used in the two-pack acryl-urethane coating material of this invention will be explained.

The polyisocyanate compound used in the present invention is a polyisocyanate compound having at least two isocyanate groups in one molecule, and preferably 3 or more isocyanate groups in one molecule, and more preferably it is a yellowing--roof type of, non-aromatic, polyisocyanate compound having 3 or more isocyanate groups in one molecule. As such a polyisocyanate compound, there are cited diisocyanate compounds such as hexamethylene 1,6-diisocyanate, isophorone diisocyanate, hydrogenated product of diphenylmethane-diisocyanate and the like; polyisocyanate compounds composed of a condensate of a diisocyanate 11 CO o o C So o 0o 0 CC 0 0r 0 0 C 00 CO3 C D C" C CS 1 compound and a polyhydric alcohol such as trimethylolpropane and the like; polyisocyanate compounds composed of a self-condensate of a diisocyanate compound, and the like. Concrete examples of the condensation type polyisocyanate compound include Colonate N manuractured by Nippon Polyurethane K. K. and Sumidule N, Desmodule E 3150 and Desmodule E 3260 manufactured by Sumitomo Bayer Polyurethane K. K. (all yellowing-proof).

Preferably, the above-mentioned polyisocyanate 10 compounds are used in the form of a solution diluted with a solvent such as ethyl acetate, butyl acetate, xylene or the like. Since commercial polyisocyanate compounds are usually available in the form of a solution in an organic solvent, they can be used as they are.

The proportion of the polyisocyanate compound to the graft polymer as the main ingredient may be comparable to that in the prior two-pack acryl-urethane coating materials using an acryl-polyol and a polyisocyanate compound. For example, when the amount of the monomer unit having a functional group reactive with isocyanate group (hereinafter referred to as a NCO-reactive functional group) present in the graft polymer is about 5% by weight or less, the amount of the total isocyanate groups in the polyisocyanate compound used should preferably be about 1 to 1.2 moles per one mole of the total NCO-reactive .functional groups.

The two-pack acryl-urethane coating material of this invention comprising a graft polymer prepared

I

E

i 4i 0, 12 M W i 404 00 0 go v 0l 0 0 00 0 0 1, 40 1 by the macromonomer method wherein the graft component is well controlled in the degree of polymerization and content, is much superior to the prior two-pack acrylurethane coating materials in the rapid drying property.

In addition, it is excellent in the gloss and weather resistance. Further, since it requires no use of a ketone type organic solvent such as methyl ethyl ketone, methyl isobutyl ketone and the like, it does not injure a plastic substrate such as ABS resin substrate when 10 applied to the surface of the substrate. Thus, it can be applied to extensive uses and is quite useful industrially.

Next, this invention will be explained more concretely by way of the following Referential Examples, Examples and Comparative Examples. In all of these examples, the term "parts" means "parts by weight".

Referential Example 1 i) Synthesis of Macromonomer Into a glass flask equipped with a stirrer, a 20 reflux condenser, a dropping funnel, a thermometer and a nitrogen gas inlet tube was charged 106 parts of butyl acetate as a solvent. Then, a mixture consisting of 100 parts of methyl methacrylate (hereinafter referred to as MMA), 3.0 parts of mercaptoacetic acid and 2 parts of azobisisobutyronitrile (hereinafter referred to as AIBN) was continuously dropped into the flask over a period of 5 hours at 80 to 85 0 C while introducing Q u 0 0 0 f0 00 0 *u 0 *i o O 4 fl 9 1;i F' Aii i t 13 -Z i -r L- C--il Y I "----rr*rrul .r 14(1 a no o 00, 000n 0 oo a 00 00 0 00 00 4r 4Q 1 nitrogen gas, to carry out a polymerization reaction.

Acid number of the prepolymer thus obtained, originated from its terminal carboxyl group, was measured, and it was found to be 0.15 meq/g. After heating the prepolymer at 130 0 C for one hour to vaporize off the volatile substances contained therein, the concentration of the prepolymer was 50%. Then, to 200 parts of the polymerization product thus obtained, 6.0 parts of glycidyl methacrylate to be reacted with the carboxyl group of 10 the prepolymer (corresponding to 1.4 equivalents per one equivalent of the carboxyl group of the prepolymer), 1 part of tetrabutylammonium chloride as a catalyst (0.42% by weight as expressed by concentration in the total mixture) and 0.05 part of hydroquinone monomethyl ether as a polymerization inhibitor (250 ppm by weight as expressed by concentration in the total mixture) were added, and the resulting mixture was kept at 90 0 C for 9 hours. The resultant solution containing the terminal methacryloyl group-containing methyl methacrylate type macromonomer had an acid number of 0.001 meq/g or below, which means that conversion of carboxyl group to methacryloyl group was or above. Degree of coloration of the solution was 48 as expressed in terms of APHA, and number average molecular weight of the macromonomer (calculated as polystyrene) was 3,500 as measured by

GPC.

ii) Synthesis of Graft Polymer Into 100 parts of butyl acetate/xylene solvent 14 1

I

14 i L. as the acryl-polyol, a graft polymer prepared by grafting a side .chain of alkyl acrylate or the like onto cellulose la- No N MMO o 0 00 00 01 L3aO o 9 C, 9 9 C 00 0 9 9 00 00 90 c* a 1 mixture (1:1 by volume) were dissolved 60 parts of the polymerization reaction product obtained in i) containing the macromonomer, 50 parts of MMA, 13 parts of ethyl acrylate, 27 parts of butyl methacrylate, 4 parts of styrene, 5 parts of 2-hydroxyethyl methacrylate, 1 part of acrylic acid and 3 parts of AIBN. Then, the mixture was heated to 70 0 C and radical-pc-ymerized to prepare a graft polymer having a weight average molecular weight of 30,000.

Example 1 The main ingredient of a two-pack coating material was prepared by mixing together 60 parts of the graft polymer solution obtained in Referential Example 1 (this solution had a solid concentration of 50% by 15 weight), 30 parts of titanium white as a pigment, 0.3 part of various coating additives in the total and parts of a thinner.

The main ingredient thus obtained had a solid concentration of 55% by weight. Proportion of the pigment to the total solid content (hereinafter referred to as PWC) was 55% by weight. Its viscosity was 113 seconds as measured with Ford cup.

One hundred parts of the main ingredient was compounded with 5 parts of Sumidule N (aliphatic polyisocyanate, a solution in cellosolve acetate/xylene having a solid concentration of 75%, viscosity 250 100 mpa.S (20 0 manufactured by Sumitomo Bayer 15 4t 4 i, i_ LLI_-I~ 1Urethane K. and 20 parts of a thinner, and the resulting mixture was thoroughly homogenized by agitation.

The coating materi al thus prepared was coated onto a steel plate and the coating film was evaluated on its properties in the following manner.

Drying property: Evaluated according to tackiness by touching it with a finger after standing J for 3 hours at Pencil hardness: Manual scratching method 0 0 0 00 10 using MITSUBISHI Hi-Uni pencil.

o 0 Gloss (600): JIS K5400 6.4.

a Xylene resistance: 10 shuttle rubbings.

Benzine resistance: Immersion in testing benzine No. 2 for 4 hours, followed by evaluation of appearance.

Hot water resistance: Heating at 50'C for 0024 hours, followed by immersion in water at 401C for one hour and evaluation of appearance.

Weathe resistance: Exposure in Sunshine Weather-O-Meter for 1,200 hours, followed by measurement of gloss (600) according to JIS K5400 6.4; expressed by difference from blank.

The results are shown in Table 1.

Comparative Example 1 A main ingredient was prepared from a commercial acryl-polyol of which monomer unit constitution is shown below, and the same kinds and amounts of pigment and -16the followings: aromatic vinyl compounds such as styrene, a-methylstyrene and the like; cyano-vinyl compounds such 3 -i lir iy 1 additives as used in the main ingredient of Example 1.

The main ingredient thus obtained was compounded with the same crosslinking agent. Sumidule N as in Example 1 so that the molar ratio of hydroxyl groups in the polymer of the main ingredient to isocyanate groups in the crosslinking agent became equal to that in Example 1. Thus, a coating material was obtained.

On the coating material thus obtained, its properties were evaluated in the same manner as in "I 10 Example 1. The results are shown in Table 1.

0 0 0 Formulation of acryl-polyol: o MMA unit 50 parts o Ethyl acrylate unit 8 parts 0 0 Butyl methacrylate unit 10 parts oooo.0 2-Hydroxyethyl methacrylate unit 10 parts 0 1 So, Acrylic acid unit 2 parts S17the monomer unit derived from these monomers must be lower than 25% by weight. If its content is not lower 4 ~i -li l ~C Table 1 Comparative Properties Example 1 Example 1 (Acryl lacquer) Film thickness 40 Drying property o x Penci:l hardness H B Gloss 90 Xylene resistance o o Benzine resistance o o Hot water resistance o o Weather resistance 2 4 Do Co oo 0 O 00 o 00 00 0 0 0 0 00 1 It is apparent from Table 1 that, as compared with the prior two-pack acryl-urethane coating material, the coating material of this invention is remarkably improved in drying property and excellent in pigment 5 dispersibility and, as the result, it is excellent also in gloss.

Referential Example 2 Using the same apparatus as in Referential Example 1, a terminal carboxyl group-containing prepolymer was synthesized by repeating the procedure of Referential Example 1, except that the MMA monomer was replaced with a mixture consisting of 70 parts of MMA, 25 parts of 18 ii. i

'S

_LII~TeSL~-- -^--IIIYLYY I 0 01

C

t0 C V Cr C 1s0 0I 0 00 4 06 0 1 styrene and 5 parts of 2-hydroxyethyl methacrylate and that the butyl acetate used as a solvent was replaced with toluene. Then, the carboxyl group was converted to methacryloyl group to prepare a terminal methacryloyl group-containing styrene type macromonomer. Degree of coloration of the reaction mixture thus obtained was as expressed by APHA, and number average molecular weight of the macromonomer itself was 4,000.

Then, 60 parts of the reaction mixture contain- 10 ing the macromonomer obtained above was compounded with 30 parts of isobutyl acrylate, 50 parts of MMA, 19 parts of CAB, 1 part of methacrylic acid and 3 parts of AIBN, and the resulting mixture was dissolved into 100 parts of butyl acetate/toluene solvent mixture (1:1 by volume).

Then, the resulting solution was heated to 70 0 C and radical-polymerized to obtain a graft polymer having a weight average molecular weight of 30,000.

Referential Example 3 A terminal acryloyl group-containing macromonomer was synthesized by repeating the procedure of Referential Example 1, except that a prepolymer was prepared by using a monomer mixture consisting of 90 parts of MMA and parts of diethylaminoethyl acrylate in place of the monomer MMA used in Referential Example 1 and that parts of glycidyl acrylate was reacted in place of the glycidyl methacrylate used in Referential Example 1.

Degree of coloration of the macromonomer solution thus 19 k

I

1 obtained was 56 as expressed by APHA, and the macromonomer itself had a number average molecular weight of 4,000.

Then, 60 parts of the reaction mixture containing a macromonomer obtained above was compounded with parts of isobutyl acrylate, 50 parts of MMA, 19 parts of CAB, 1 part of methacrylic acid and 3 parts of AIBN, and the resultant mixture was dissolved into 100 parts of butyl acetate/toluene solvent mixture (1:1 by volume).

Then, the resulting solution was heated to 70 0 C and Sradical-polymerized to obtain a graft polymer having a weight average molecular weight of 30,000.

0 Examples 2 and 3 Each of the graft polymer solutions obtained o°o 15 in Referential Examples 2 and 3 (60 parts each) (each of s a, the solutions had a solid concentration of 50% by weight) was compounded with 15 parts of titanium white and parts of ferric oxide as pigments, 0.5 part of various coating additives in the total and 20 parts of a thinner (1:1 by weight mixture of butyl acetate and toluene).

Thus, main ingredient A for two-pack coating material was obtained from the graft polymer of Referential Example 2, and main ingredient B was obtained from the graft polymer of Referential Example 3.

The main ingredients A and B thus obtained both had a solid concentration of 55% by weight and PWC of 50% by weight. As measured with Ford cup, 20 1 ingredient A and ingredient B had viscosities of 105 seconds and 125 seconds, respectively.

One hundered parts of each of main ingredients A and B was compounded with 10 parts of Sumidule N to prepare coating material A (Example 2) and coating material B (Example respectively.

Each of the coating materials thus obtained was coated onto a substrate composed of ABS resin, and the coating film was evaluated on its properties in the same manner as in Example 1. The results are shown in Table 2.

Table 2 I #l t tI 1 I od t p~ p p 0 Properties Example 2 Film thickness (p) Drying property Pencil hardness Gloss Hot water resistance Weather resistance Example 3 o

H

91 o 3 Further, in using any of these two coating materials, the organic solvent present in the coating material did not injure the substrate.

21 fc-tlBTO tja~a ^M L «ifc«ii im n «ili[g 1 Comparative Example 2 A main ingredient was prepared by mixing .0 parts of CAB dissolved in a solvent mixture consisting of cellosolve acetate, methyl ethyl ketone and toluene (30/30/40 by volume) with 20 parts of an acrylic copolymer having the undermentioned monomer composition. A coating material was prepared from the main ingredient and Sumidule N as a crosslinking agent, and the coating material was coated onto a substrate composed of ABS 10 resin. As the result, the substrate was swollen to some a i" a "a extent by the organic solvent in the coating material.

o Composition of acrylic copolymer a a o, a MMA unit 68 parts Lauryl methacrylate unit 20 parts au Ethyl acrylate unit 10 parts oa Itaconic acid unit 2 parts.

0a 2 a 4 t i 22

Claims (10)

1. A two-pack acryl-urethane coating material comprising: a graft polymer having, in its molecule, a functional group reactive with isocyanate group obtained by radical-copolymerizing a macromonomer having a number average molecular weight of 1,000 to 20,000 and a (meth)- acryloyl group on its one molecular end and containing by weight or more, based on the summed amount of total monomer units, of a monomer unit derived from a monomer represented by the following general formula: CH 2 CR1R 2 wherein R 1 represents H or CH 3 and R 2 represents phenyl group, nitrile group or group -COOR 3 (R 3 is a saturated aliphatic or alicyclic hydrocarbon group having 1 to carbon atoms) with an alkyl (meth)acrylate or with an alkyl (meth)acrylate and another monomer copolymerizable with it; and (ii) a polyisocyanate compound.

2. An acryl-urethane coating material according to Claim 1, wherein said monomer represented by general formula CH 2 CR1R 2 is selected from the group consisting of aromatic vinyl compounds such as styrene, a-methyl- styrene and the like; cyano-vinyl compounds such as acrylonitrile, methacrylonitrile and the like; methacrylic esters such as methyl methacrylate, ethyl methacrylate, I i 23 I 0 ur oo 0 o 0a 00 0 0o 0 butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and the like; and acrylic esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate and the like.

3. An acryl-urethane coating material according to Claim 1, wherein the macromonomer-forming monomer other than the monomer represented by general formula CH 2 CR R 2 is selected from the group consisting of vinyl carboxylates such as vinyl acetate and the like; vinyl ethers such as vinyl propyl ether, vinyl butyl ethers and the like; hydroxyl group-containing (meth)- acrylic esters such as 2-hydroxyethyl(meth)acrylate, hydroxypropyl (meth)acrylate, polyethylene glycol mono- (meth)acrylate and the like; aminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate, diethylamino- ethyl (meth)acrylate and the like; and maleic anhydride.

4. An acryl-urethane coating material according to Claim 1, wherein the functional group reactive with isocyanate group with the graft polymer has, is selected from the group consisting of hydroxyl group, carboxyl group, amino group and group C C 0 0 0 An acryl-urethane coating material according to Claim 1, wherein said alkyl (meth)acrylate to be radical-copolymerized with the macromonomer is selected from the group consisting of methacrylic esters such 00: 00 4 o a O 4s 24 a a~ o 0 ai( 0 00 04 4 4r 4 4 44 4 as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacryalte, lauryl methacrylate and the like; and acrylic esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate and the like.

6. An acryl-urethane coating material according to Claim 1, wherein said another monomer copolymerizable with the alkyi (meth)acrylate to be radical-copolymerized with the macromonomer is selected from the group consist- ing of styrene, a-methylstyrene, acrylonitrile, meth- acrylonitrile, vinyl chloride, vinyl acetate, N-methylol- acrylamide, acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxyethyl dcrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylamino- ethyl acrylate, itaconic acid and maleic anhydride.

7. An acryl-urethane coating material according to Claim 1, wherein the amount of the alkyl (meth)- acrylate to be radical-copolymerized with the macromonomer is 50% by weight or mc'.e based on the summed amount of said alkyl (meuLL)acrylate and another monomer copolymer- izable with the alkyi (meth)acrylate.

8. An acryl-urethane coating material according to Claim 1, wherein the content of the monomer unit 25 AIBN) was continuously dropped into the flask over a period of 5 hours at 80 to 85 0 C while introducing 13 i i MIPI* i ~--lrlll ~1_11_ ^IL__I~---CICII I1 V0 0 0Q 016 00 t O 0 at having the functional group reactive with isocyanate group in the graft polymer is 0.1 to 20% by weight based on the summed amount of total monomer units.

9. An acryl-urethane coating material according to Claim 1, wherein said graft polymer is produced by the use of cellulose acetate butyrate in addition to the macromonomer. An acryl-urethane coating material according to Claim 1 which comprises the prior acryl-polyol in addition to the graft polymer.

11. An acryl-urethane coating material according to Claim 1, wherein said isocyanate compound is a non- aromatic polyisocyanate compound having three or more isocyanate groups in one molecule.

12. An acryl-urethane coating material according to Claim 1, wherein said polyisocyanate compound is selected from the group consisting of diisocyanate compounds such as hexamethylene 1,6-diisocyanate, isophorone diisocyanate, hydrogenated product of diphenylmethane diisocyanate and the like, polyiso- cyanate compounds composed of condensation products formed between a diisocyanate compound and a polyhydric alcohol such as trimethylolpropane and the like, and polyisocyanate compounds composed of self-condensation products of a diisocyanate compound. Dated this 22nd day of March 1989 TOAGOSEI CHEMICAL INDUSTRY CO.,LTD. Patent Attorneys for the Applicant F.B. RICE CO. 26