AU598935B2 - Coating composition having improved weathering resistance and recoating property and resinous composition to be used therein - Google Patents

Description

)i__U COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 A7ce Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: us ur,2nt1t W&de 1w9 i.Jd~~n IL~ Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: NIPPON PAINT COMPANY, LIMITED 102, Oyodokita 2-chome, Oyoda-ku, Osaka-shi, Japan.

HIROTOSHI UMEMOTO, HISAKI TANABE and YUTAKA TAKEUCHI GRIFFITH HACK CO 71 YORK STREET SYDNEY NSW 2000 Complete Specification for the invention entitled: 0 COATING COMPOSITION HAVING IMPROVED WEATHERING RESISTANCE AND RECOATING PROPERTY AND RESINOUS COMPOSITION TO BE USED THEREIN The following statement is a full description of this invention, including the best method of performing it known to me/us:- 6650A/as a \i ii i i i; i r i oor

D

rri The present invention relates to a coating composition for top-coat use having improved weathering resistance and recoating property and a resinous composition to be used therein.

A coating composition containing as essential components a binder composition comprising hydroxyl bearing heat curable resin and aminoaldehyde resin and/or isocyanate compound, and pigment has been widely used in various fields because of its capability of giving a cross-linked tough coating through baking. However, depending on the kind of base resin used, coating performance, application characteristics, appearance and the like are divided in every case, and with the diversification in needs, further improvements in film performance and especially weathering resistance have been longed for.

As the resinous binder for coating compositions, a combination of oil-free polyester and aminoaldehyde resins has been well known and watched with keen interest because of having improved properties as weathering resistance, mechanical properties of the coating, interlaminar adhesion and the like. However, since there is a trend of easy generation of cratering and uneven loss of gloss and since polyester has relatively poor compatibility with amino resin, such combination has not been used so widely.

25 Recently, many important facts have been found out such that by the use of saturated alicyclic polybasic acid or the combination of saturated alicyclic polybasic acid and aromatic polybasic acid as a part of acid component of oil-free polyester resin, considerable improvements in application characteristic, uneven loss of gloss, compatibility with amino resin, gloss and curing property can be attained, and that by the modification of polyester resin with a reactive organopolysiloxane resin, weathering resistance can be improved, and that by making polyester resin with saturated alicyclic polybasic acid and then subjecting to a silicon modification, a further improvement in application characterists (pinhole, 3agging

*J

6207S/as 1A- L i i i, ii i o 441I and cratering resistances), gloss and weathering resistance can be obtained, and on the basis of these findings, polyester based coating compositions have suddenly become the object of public attention as top-coats for automobile coil coating and the like.

However, when polyester resin is subjected to a silicon modification, an improvement in weathering resistance is indeed realized but an additional problem of decreased recoatability is always brought out. Therefore, in order to make a polyester base composition for use as a top-coat, it is essential that the composition has the features of recoatability as well as weathering resistance.

The inventors, with the object of improving both recoatability and weathering resistance of polyester resin based composition, have made endeavour and found that improvement in weathering resistance of the polyester composition is most advantageously achieved by the abovesaid silicon modification and the loss of recoatability in such composition can be effectively cured by the introduction of a particular alkyleneimine moiety thereto, and that such means can successfully be applied to resins other than polyester, as well.

Accordingly, the present invention provides a coating composition comprising a silicon modified resin having a number average molecular weight of between 500 and 2000 and which is obtained by subjecting a base resin having both hydroxyl and carboxyl groups to a silicon modification with an organopolysiloxane resin represented by the formula: R nSi(OR')m 0 4 n m 2 wherein R is a monovalent organic group attached to Si through C-Si bonding; R' is hydrogen, C 1 to C 20 alkyl or aryl group; and n and m each represents a real number of 4 or less, provided that n m is less than or equal to 4, and 6207S/as I_ 2 m 1 C L_ a polyethyleneimine of the formula: S-CH-CH

-N

or NH 2 CH 2 CH (CH 2 CH

CH

2

CH

2

-N-

wherein R is hydrogen, substituted or unsubstituted C 1 to

C

20 alkyl or aryl group; n is an integer from 3 to 2000; x is an integer from 0 to 1000; and y is an integer from 3 to 2000, wherein the weight ratio of is 95 to 99.99/5 to 0.01.

In the parent invention application no. 35336/84, a base resin bearing both hydroxyl and carboxyl groups is o reacted, in any successive order, with an organopolysiloxane .o resin and an alkylene imine compound.

As the base resin, any of the resins having both O 20 hydroxyl and carboxyl groups may be satisfactorily used.

S0 S' Examples of such resins are polyester resin, alkyd resin, acrylic resin and the like customarily used as resinous vehicle in coating composition.

The inventors found and disclosed in the parent application no. 35336/84 that when hydroxyl groups of such resin are reacted with reactive organopolysiloxane resin, thereby effecting silicon modification of the resin, the weathering resistance is markedly improved.

As the reactive organopolysiloxane resins to be used mention is made of such members as stated in Japanese Patent Application Kokai No. 157461/81 and 157462/81, and represented by the formula R Si(OR') 0 n mSi(OR') 4 n m 2 wherein R is mono-valent organic group attached to Si through C-Si bonding, R' is hydrogen, C 1 to C 20 alkyl or aryl groups; and n and m each represents a whole number of 4 and less, 6207S/as 3providing that n m is less than 4, and having a number average molecular weight of about 500 to 2000.

Such organopolysiloxane resin should preferably have 2 and more reactive groups OR' as hydroxy and alkoxy which are caused to react with hydroxyl groups of the base resin through dehydration and dealcoholization, thereby effecting the silicon modification of the base resin.

o o Examples of such silicon resins are Z-6018 °a (Dow Corning Co., oo R OSi--S i R 0 o Ooo I I Si 0 0 Si HO 0-Si--Si 0

OH

S R=CH Molecular weight 1600), Z-6188 (Dow Corning Co., R R R R R=CH3' S* CH 3-Si-O-Si-O-Si-O-Si-OCH 3 3 I R OCH 3 R R Molecular weight 650), Sylkyd 50, DC-3037 (Dow Corning Co.), KR-216, KR-218, KSP-1 (Shinetsu Silicon Co.), TSR 160, TSR-165 (Tokyo Shibaura Elect. Co.), SH-5050, SH-6018, SH-6188 (TOray Silicon Co.) and the like.

For the silicon modification of base resin, it is in general -4-

I

YUi preferred to react 20 to 97 parts by weight of base resin with 80 to 3 parts by weight of reactive organopolysiloxane resin (all in solid weight).

This is because, the desired improvement in weathering resistance cannot be expected with a lesser amount, i.e.

than 3 parts by weight, of organopolysiloxane resin and at a higher level of more than 80 parts by weight, there is a trend that compatibility of base resin with organopolysiloxane resin is getting worse and hence they are hardly reacted with each other.

The inventors further found and disclosed in the parent application number 35336/84 that the loss of recoatability accompanied with the silicon modification of base resin may be effectively recovered by the modification with an alkyleneimine compound.

As already stated, the present base resin bears Scarboxyl groups and therefore, when reacted with a compound having at least 1 C2 to C3 alkyleneimine ring, the said ring is first opened and reacted with said carboxyl groups, thereby attaining the alkyleneimine modification of the base resin.

The alkyleneimine compounds employed in the present invention may include the following: I a RK R 6

R

3 22' R -C-R4 1 6 4 4* «N

R

wherein R

I

R

2

R

3

R

4 and R 5 each represents hydrogen; alkylgroup having 20 and less carbon atoms as methyl, ethyl, 6207S/CF L_ mo d propyl and the like; aryl like phenyl; alkaryl as tolyl, xylyl and the like; aralkyl as benzyl, phenethyl and the like; and

R

6 represents hydrogen or alkyl generally having less than 6 carbon atoms; and n is 0 or 1.

The above mentioned groups each may further include substituents which will give no harmful effect on the fundamental properties of imine group. Examples of such substituents are carbonyl, cyano, halogen, amino, hydroxyl, S alkoxy, carbalkoxy and nitrile.

i'd Typical examples of said alkylene imine compounds are ethylene imine, 1,2-propylene imine, 1,3-propylene imine, 1,2dodecylene imine, 1,1-dimethyl ethylene imine, phenyl ethylene imine, tolyl ethylene imine, benzyl ethylene imine, 1,2diphenyl ethylene imine, 2-hydroxyethyl ethylene imine, aminoethyl ethylene imine, 2-methyl propylene imine, 3chloropropyl ethylene imine, p-chlorophenyl ethylene imine, 4000 methoxyethyl ethylene imine, carboethoxyethyl ethylene imine, N-ethyl ethylene imine, N-butyl ethylene imine, N-(2- S aminoethyl) ethylene imine, N-(2-hydroxyethyl) ethylene imine, N-(cyanoethyl) ethylene imine, N-phenyl ethylene imine, Ntriethyl ethylene imine, N-(p-chlorophenyl) ethylene imine, N- (2-carboethoxy-l-ethyl) ethylene imine.

From the standview of availability and effectiveness, particularly preferable members are ethylene imine, 1,2propylene imine and N-(2-hydroxyethyl) ethylene imine.

In the inve-tion, other alkylene imines than those of the abovementioned general formula may be satisfactorily used, -6- 'i I r- -I providing having at least 1 C 2 to C 3 alkylene imine ring.

Examples are ethylene-l,2-bisaziridine and 1,2,4-tris(2-l-aziridinyl ethyl) trimellitate and the like.

The above-mentioned alkylene imine compound must be reacted with the base resin in an amount corresponding to resinous acid value of 0.1 to 50. In other words, it is essential that the alkylene imine compound be reacted with the base resin in an amount of 2 x 10-4M to 1 x 10-1M Wt% of the resin, wherein molecular weight of alkylene imine M number of alkylene imine groups contained in a molecule of alkylene imine compound This is because, if the amount of alkylene imine compound is less than the abovesaid lower limit, then the effect of said modification cannot be fully attained, whreas 0 a if the said amount exceeds over the abovementioned upper limit, then there are considerable lowering in film performance due to the severe yellowing of the coating and 0 when compounded with cross-linking agent, there may often S occur deficient curing. Either of the abovesaid silicon modification and alkylene imine modification may be easily o carried out by mere heating the mixture of starting resin and reagent, in the presence or absence of solvent, at a temperature of less than 200 0 C, preferably less than 150 0

C.

In a particularly preferable embodiment of the invention, disclosed in the parent application number 35336/84 the base resin is first subjected to a silicon Smodification and then to an alkylene imine modification.

However, it is possible to effect the alkylene imine modification in the first step and the silicon modification in the subsequent step, and if desired, these two may be effected simultaneously.

Though the invention is applicable to any base resins providing having both hydroxyl and carboxyl groups, particularly advantageous application is for the modification of polyester resin and inter alia, such -7- 6207S/CF polyester resin as having saturated alicyclic polybasic acid in an amount of at least 25%, preferably at least 40% of the total acid components.

By the adoption of such conditions, particualrly excellent weathering resistance and recoating properties are obtained, as well as the improved application characteristics, appearance and other film performance required for a top-coat paint composition.

Therefore, in the second aspect of the invention as disclosed in the parent application number 35336/84, a coating composition based on the abovesaid modified resin composition is provided.

That is, in the parent invention, is provided a coating composition having improved weathering resistance and recoatability and consisting essentially of S- hydroxyl bearing thermosetting resin, o° aminoaldehyde resin and/or isocyanate compound, and pigment, S characterizing by using as resin, such resin as being 0 2V i I -8- 6207S/CF i~ i i I _I_ obtained by subjecting a base resin having both hydroxyl and carboxyl groups to a silicon modification with an organopolysiloxane resin represented by the formula: h Si(R' n 4 n m 2 (wherein R is monovalent organic group attached to Si through C Si bonding; R' is hydrogen, C 1 to C 20 alkyl or aryl group; and n and m each represents a real number of 4 and less, providing satisfying the condition n m 4 S° and having a number average molecular weight of about 500 to 2000, Sand to an alkylene imine modification with an alkylene imine Scompound having at least 1 C 2 to C 3 alkylene imine ring.

As already stated, the abovesaid silicon and alkylene imine modifications may be carried out with the base resin in any desired order.

The component is a cross-linking agent selected from amino aldehyde resin and/or isocyanate compound.

As the amino aldehyde resin, mention is made of such resins as having melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine as an amino component.

Any of the aminoaldehyde resins commonly used in coating compositions may be successfully used in the present invention. Among them, the most preferable one is melamine formaldehyde resin from the standview of weathering resistance.

-9- To these aminoaldehyde resins, it may be possible to add conventional curing catalyst for lowering the curing temperature.

Examples of isocyanate compounds are polyisocyanates as tolylenediisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate) and the like, and blocked type polyisocyanates as the abovesaid polyisocyanates blocked with aliphatic or aromatic monoalcohol, phenol, oxim, caprolactam and other conventional 1. 0, blocking agent. Typical examples of said blocked type 0 o °oo'o polyisocyanates are Takenate B-815N, Takenate B-840N (Takeda o Yakuhin Adduct B 1065 (Veba Chemie, West Germany); Additol VXL-80 (Hoechst Japan) or the like.

When blocked type polyisocyanates are selected one may use catalyst capable of accelerating the release of blocking agent

S

4 therefrom.

4 34 S The abovesaid aminoaldehyde resins and polyisocyanates may be o used singularly or in combination form.

In the present invention, the solid weight ratio of said silicon and alkylene imine modified resin to aminoaldehyde resin and/or polyisocyanate should be in a range of 90/10 to 60/40.

This is because, if the amount of said cross-linking agent (B) is far below the abovesaid lower limit, these shows a tendency to give the results of lowering in weathering resistance, coating hardness and solvent resistance due to the deficient curing, whereas if it is far excess over the abovesaid upper ii limit, the coating will become brittle.

As the pigment, any of organic and inorganic pigments customarily used in coating compositions may satisfactorily be employed in an amount of less than 100 PHR. If the pigment concentration is higher than 100 PHR, there is no weathering resistance at all.

The coating composition can be prepared by using the aforesaid binder and pigment components.

If desired,the composition may be added with other conventional coating additives as surface conditioner, UV absorber, antisettle agent, antioxidant, wetting agent, diluent and the like.

No particular device is required for applying the composition and usual application methods as brushing, spraying, dipping and the like may satisfactorily be used.

Th inventors have found that the abovesaid improvements o%.'oin weathering resistance and recoatability may be likewise obtained with the mere mixture of silicon modified resin and o o 0o particular polyethylene imine. Thus, this invention ""provides a coating composition consisting essentially of 0 o silicon modified resin, and polyethylene imine represented by the formula: 2 -CH 2 CH2-N- o2 2 o R 0 0 t 300 -11- 6207S/CF or NH 2

-+-CH

2 CH 2 -CH

CH

2 C 2 I

-N-

wherein R is hydrogen, substituted or unsubstituted C 1 to C 2 0 alkyl or sryl group, n is an integer of 3 to 2000, x is 0 to 1000, and y is 3 to 2000, the weight ratio of being to 99.99 5 to 0.01.

As the silicon modified resins, mention is made of silicon 0 modified polyester resin, silicon modified alkyd resin, "o ao silicon modified acrylic resin as disclosed in Japanese Patent S Application Kokai Nos. 21493/72, 157461/81, 157462/81 and the like.

Usually, such resins may be prepared by mixing base resin, as polyester, alkyd and acrylic resins, with a reactive organopolysiloxane resin of the formula: R Si(OR') O n4 n- m n m S2 in which R, n and m are as defined above, and heating the mixture.

Since the silicon modified resins are the same materials as used in the first invention as intermediates for the preparation of silicon and alkylene imine modified resins, no additional explanations would be required thereupon.

The polyethylene imines used in this third invention are represented by the formula: -12-

CH

2

-CH

2

-N

1 I in

R

or NH -CH CH-N CH 2-CH2-NH-4-

CH

2

N

They are easily available in the market or prepared by the methods known per se., if desired.

Examples of such resins are Epomin SP-003, SP-006, SP-012, SPi.0o.. 018, SP-103, SP-110 manufactured by Nihon Shokubai Kagaku oo 0 Kogyo molecular weight 250 to 1800 Epomin SP-200, SPao 300 (manufactured by Nihon Shokubai Kagaku Kogyo K.K., molecular weight 10000, 30000), Epomin P-1000, P-1020 S (manufactured by Nihon Shokubai Kagaku Kogyo molecular weight 70000, 100000), Polyethyleneimine 210T (manufactured by S Sogo Yakkoh, viscosity 19000 to 23000 cps, 50% aqueous Ssolution), Polyethyleneimine 15T (manufactured by Sogo Yakkoh, iis viscosity 1000 to 2000 cps) and the like.

Particularly preferable members are Polyethyleneimine 210T and Polyethyleneimine Such polyethylen imine is usually used in an amount of 5 to 0.01 parts by weight (solid basis) to 95 to 99.99 parts by weight of silicon modified resin.

If the amount of polyethylene imine is too small, one cannot expect the desired effect of recovering the recoatability and if it is too excessive, there is a trend that weathering -13i -d -i L i resistance, chemical resistance, water resistance and the like be lost out.

For the preparation of coating composition, it is only required to combine the silicon modified resin and polyethylene imine in the defined weight ratio and mix well at a room temperature.

In this invention, a cross-linking agent as melamine formaldehyde resin and polyisocyanate is optional. If desired, the composition may include pigment, surface conditioner, UV absorber, antioxidant, wetting agent and other conventional additives.

The present coating composition is useful as both intercoat and top coat. The invention shall be now more fully explained in the following Examples numbered 24-30 and comparative Examples 13 to 17 which are not intended to o limit the invention in any way. The other Examples are included for interest only.

o o -14- 6207S/CF L7 1 1- Example 1 Into a reaction vessel fitted with heater, stirrer, reflux condenser, water separater, fractionating column and thermometer, were placed 19.4 parts of hexahydro phthalic anhydride, 22.6 parts of trimethylol propane, 26.5 parts of neopentylglycol and 30.1 parts of 1,6-hexanediol and the mixture was heated. When the charged materials were melted and brought to the condition capable of being stirred, stirring was commenced to do and temperature was raised to .10q2 210"C. From 210"C to 230"C, said temperature was increased at a consta, speed in 2 hours and the formed water was removed out of ne system during said heating. When reached to 230°C, the mixture was maintained at the same temperature until the resinous acid value of 1.0 and then allowed to cool.

After cooling, 83.1 parts of isophthalic acid were added and again heated to 190'C. From 190"C to 210"C, said temperature I 14 was raised at a constant speed in 3 hours, during which time Sthe formed water was removed out of the system continuously.

When reached to 210*C, 3.2 parts of xylene were added and the reaction was switched to condensation in the presence of solvent. At the stage when resinous acid value come to 20.0, the mixture was allowed to cool and then added with 29.3 parts of xylene and 75.9 parts of Cellosolve acetate to obtain an oil-free polyester resinous varnish A (ahereinafter called as base resin A).

Next, 28.7 parts of reactive silicon resin DC-3037 (Dow Corning Co.) and 0.38 part of TBT-100 (tetrabutyl tianate, is condensation catalyst, manufactured by Nihon Soda were added and the mixture was heated and stirred. The reaction was continued at 140°C until the formed and recovered methanol quantity reached to 75% of the theoretical amounts (which is the methanol quantity at the time when 100% of methoxy groups in the reactive silicon resin are reacted with hydroxyl groups of the polyester resin), and then the mixture was allowed to cool. Finally, 0.9 part (corresponding to res-inous acid value to be consumed by the reaction of 3.0) of N-(2-hydroxyethyl) «iQ ethyleneimine (HEEI, trade mark of Sogo Yakko was added ao and the mixture was heated at 80'C for 1 hour and then allowed 44 04 0 o to cool. After cooling, 5.8 parts of xylene and 13.6 parts of Cellosolve acetate were added to obtain an alkyleneimine modified silicon polyester resin varnish I. This varnish showed the characteristics of non-volatile content of 60.5%; S varnish viscosity (Gardner's viscosity, 25'C) of R-S; and Sos resinous acid value of 15.0.

0 04 Examples 2 and 3 Two batches of the same silicon modified polyester resin varnish as stated in Example 1 were prepared. To one of the batches, 1.8 parts (corresponding to resinous acid value to be consumed by the reaction of 6.0) of HEEI and to the other batch, 3.0 parts (corresponding to resinous acid value to be consumed by the reaction of 10.0) of HEEI were added and reacted as in Example 1 to obtain alkyleneimine modified silicon polyester resin varnished 2 and 3. The chracteristics of these varnishes are shown in Table 1.

-16- Example 4 Following the prescription shown in Table 1 and using the same procedures as given in Example 1, polyester resin (resinous acid value 60.0) was prepared (base resin This resin was subjected to silicon modification and alkyleneimine modification as in Example 1 to obtain resinous varnish, whose characteristics are shown in Table 1.

Example Following the prescription shown in Table 1 and using a conventional method, coconut oil was subjected to ester- °Q oexchange reaction and then condensation reaction was carried o out as in Example 1 until the resinous acid value of 20.0.

0 The reaction mixture was allowed to cool to obtain base resin C. The base resin was then subjected to silicon modification and alkyleneimine modification as in Example 1 to obtain alkyleneimine modified silicon alkyd resin varnish The characteristics of this varnish are shown in Table 1.

ota Example 6 Using the base resin A and reactive silicon resin KR-213 6 (manufactured by Shinetsu Silicon silicon modification of the base resin was carried out as in Example 1. Next, ethyleneimine (manufactured by Nihon Shokubai Kagaku Kogyo) was reacted under the same conditions as stated in Example 1 to obtain alkyleneimine modified silicon polyester resin varnish 6, whose characteristics are shown in Table 1.

Examples 7 to 9 According to the prescriptions shown in Table 1, the similar -17l.~ condensations were carried out as in Example 1 to the resinous acid values 20.0, 30.0 and 40.0, and then allowed to cool to obtain base resins D, E and F, respectively. To each of the base resins, reactive silicon resin DC-3037 was added so as to give the weight ratio of base resin silicon resin (solid) 95/5, 55/45 and 40/60, and silicon modification was carried out as in Example 1. Next, the alkyleneimine modification was carried out as in Example 1 with the respective silicon modified base resins to obtain alkyleneimine modified silicon .1 polyester resin varnishes 7, 8 and 9, whose characteristics o o are shown in Table 1.

o Example S Into a reaction vessel, were placed 45 parts of xylene and parts of Cellosolve acetate and the mixture was heated to 130"C. To this, a mixed solution of 15 parts of styrene (ST), S 42.2 parts of n-butyl methacrylate (n-BMA), 16.6 parts of lauryl methacrylate (LMA), 23.2 parts of 2-hydroxyethyl S methacrylate (2HEMA), 3.0 parts of methacrylic acid (MAA), parts of t-butyl peroxy-2-ethylhexanoate and 0.3 part of laurylmercaptane was added at a constant speed in 3 hours.

After keep warming for 30 minutes, a mixed solution of part of t-butyl peroxy 2-ethylhexanoate and 5 parts of xylene was added at a constant speed in 30 minutes and the reaction was continued at an elevated temperature for 2 hours and then allowed to cool (base resin After cooling, 17.6 parts of DC-3037 were added and the reaction was continued at 140'C while removing the formed methanol out of the system.

-18-

I

Sampling was made time by time. That is, the test sample was coated as thin film on glass plate and subjected to forced drying (130*C x 20 minutes). In the inspections made before and after drying, if the resins were thoroughly mixed together and clear coatings were observed, it was determined as final point of the reaction. At this point, the reaction mixture was allowed to cool, added with 1.1 parts of HEEI, reacted at for 1 hour and then allowed to cool. After cooling, the mixture was added with 34.2 parts of xylene to obtain an 01 alkyleneimine modified silicon acryl resin varnish oO. The characteristics of this varnish are shown in Table 1.

o Comparative Example 1 0 0 The base resin A stated in Example 1 was subjected to silicon S modification as in Example 1. Thus obtained varnish was named as varnish 11 and used for comparison's sake. The 0 c characteristics of this varnish are shown in Table 1.

0 00 Comparative Example 2 0 "QThe base resin C of Example 5 was subjected to silicon modification as in Example 1 to obtain silicon alkyd resin 2 CQo'."varnish 12, whose characteristics are shown in Table 1.

o 0 Comparative Example 3 The base resin G of Example 1U0 was subjected to silicon modification as in Example 10 to obtain silicon acryl resin varnish 13, whose characteristics are shown in Table I.

Comparative Example 4 The oil-free polyester resin varnish itself was used as comparative varnish A, whose characteristics are shown in Table 1.

-19i. I.1 S 0o o 0o 00 0 0 a 0 Q 0 ii O I 5' Table 1 Example 1 2 3 4 Composition hexahyd.phtha.anhyd. 19.4 19.4 19.4 19.4 isophthalic acid 83.1 pentol trimethylol propane 22.6 22.6 22.6 32.9 neopentylglycol 26.5 26.5 26.5 1,6-hexanediol 30.1 30.1 -30.1 56.0 coconut oil isophthalic acid 83.1 83.1 83.1 trimellitic anhydride 16.0 OH value of base resin 112 112 112 112 acid value of base resin 20 20 20 Silicon modification name of base resin A A A B amount of resin(solid) 85 85 85 silicon resin DC-3037 DC-3037 DC-3037 DC-3037 amount of silicon res. 15 15 15 Alkyleneimine modification alkyleneimine HEEI HEEI HEEI HEEI amount(in terms of resinous acid value to be consumed) 3 6 10 Varnish characteristics non-volatile content 60.3 60.6 60.8 60.1 varnish viscosity R-S S S-T X-Y resinous acid value 15.0 13.2 10.6 17.1 Name of varnish 1 2 3 4 -s

I

I

i i 0 00 Oa a r i 1 0 8 a i Table 1 (continued) Example 5 6 7 8 Composition hexahyd.phtha.anhyd. 19.4 19.4 19.4 19.4 isophthalic acid 83.1 pentol 20.2 trimethylol propane 46.3 22.6 46.7 62.5 neopentylglycol 14.7 26.5 1,6-hexanediol 16.7 30.1 43.0 34.0 coconut oil 43.2 isophthalic acid 83.1 83.1 83.1 a trimellitic anhydride 16.0 o OH value of base resin 112 112 185 300 acid value of base resin 20 20 20 Silicon modification name of base resin C A D E amount of resin(solid) 85 85 95 silicon resin DC-3037 DC-3037 DC-3037 DC-3037 Samount of silicon res. 15 15 5 Alkyleneimine modification ethylene alkyleneimine HEEI imine HEEI HEEI amount(in terms of resinous acid value to be consumed) 6 6 1 6 Varnish characteristics non-volatile content 59.7 61.5 60.7 60.4 varnish viscosity M U P-Q O resinous acid value 13.5 12.9 18.5 11.8 Name of varnish 5 6 7 8 -21-

A

K o 0 ad Table 1 (continued) Example 9 Composition ST hexahyd.phtha.anhyd. 19.4 15.0 isophthalic acid 83.1 *-142.2 pentol 30.1 *-216.6 trimethylol propane 122.4 *-323.2 neopentylglycol *-43.0 1,6-hexanediol coconut oil isophthalic acid trimellitic anhydride 16.0 OH value of base resin 500 100 acid value of base resin 40 Silicon modification name of base resin F G amount of resin(solid) 40 silicon resin DC-3037 DC-3037 amount of silicon res. 60 Alkyleneimine modification alkyleneimine HEEI HEEI amount(in terms of resinous acid value to be consumed) 6 6 Varnish characteristics non-volatile content 62.8 50.8 varnish viscosity K-L Z resinous acid value 11.3 12.9 Name of varnish 9 *-In-BMA

LMA

*-32

HEMA

MAA

2 -22- 0ooo 0 0 o o 0 0 0 4 0 0 6 0 4 Table 1 (continued) Comparative Example 1 2 3 4 Composition

ST

hexahyd.phtha.anhyd. 19.4 19.4 15.0 19.4 isophthalic acid *42.2 pentol *-216.6 trimethylol propane 22.6 46.3 *-323.2 22.6 neopentylglycol 26.5 14.7 3.0 26.5 1,6-hexanediol 30.1 16.7 30.1 coconut oil 43.2 isophthalic acid 83.1 83.1 83.1 trimellitic anhydride OH value of base resin 112 112 100 112 acid value of base resin 20 20 20 Silicon modification name of base resin A C G amount of resin(solid) 85 85 silicon resin DC-3037 DC-3037 DC-3037 amount of silicon res. 15 15 Alkyleneimine modification alkyleneimine amount(in terms of resinou acid value to be consumed) Varnish characteristics non-volatile content 60.3 59.4 50.1 60.5 varnish viscosity N-O K X-Y S resinous acid value 17.5 16.9 17.3 20.2 Name of varnish 11 12 13 A -23-

K~

i- Example 11 Using the alkyleneimine modified silicon polyester resin varnish 1 obtained in Example 1 and melamine resin as a curing agent and following the prescription given in Table 2, a blue color coating composition was prepared. Thus obtained composition was diluted with a mixed solvent of Solvesso 150 (Esso Standard Petrol. Co.) xylene butyl acetate methylisobutyl ketone 50/20/15/15, to visccosty of 23 seconds (Ford cup SPC-1 dull steel plate previously treated with zinc phosphate oco° bath and applied with an intercoat was spray-coated with the S abovesaid diluted composition and after standing for a defined 0 °0 period of time, baked at 140°C for 30 minutes. Thus obtained 4 0 4 coating was evaluated as hereinafter stated and the test results were shown in Table 2.

o 0 0 :0 Examples 12 to 18 and Comparative Examples 5 to 8 Using various resin varnishes obtained in Examples 3 to 10 and B Comparative Examples 1 to 4 and following the prescriptions shown in Table 2, blue color coating compositions were prepared, coated and evaluated as in Example 11. The test results are shown in Table 2.

-24- 200 Table 2 Example 11 12 13 14 15 16 Prescription polyester resin 35.0 3 35.0 4 35.0 6 35.0 7 alkyd resin 5 35.0 acrylic resin melamine resin *1 15.0 15.0 15.0 15.0 15.0 15.0 titanium CR-95 *2 45.0 45.0 45.0 45.0 45.0 45.0 Fastgen blue NK *3 2.3 2.3 2.3 2.3 2.3 2.3 xyl1e ne 8.0 8.0 8.0 -t 1 1 8.0 4.0 8.0 4.0 Solvesso 100 *4 4.0 4.0 n-butanol 7.0 7.0 7.0 7.0 7.0 Silicon KF-69 *5 0.015 0.015 0.015 0.015 0.015 0.015 Baking cond.

*x 30 sec. 140 140 140 140 140 140 Film performance appearance *6 0 0 0 0 gloss 93 97 98 97 96 pencil hardness *7 F-H F-H F-H F H IH weathering resis.*o 88 89 85 78 81 recoatability *8 0 0 gloss retention after 1500 hours in Sunshine Weathl-r- 0-Meter Resin weight is expressed in terms of solid weight

V

o 91 0 0 1 5 Table 2 (continued) Exampie 17 18 Comp.5 Comp.6 Comp.7 Comp.8 Prescription polyester resin 9 35.0 11 35.0 A 35.0 alkyd resin 12 35.0 acrl,,lic resin 10 35.C 13 35.0 melamine resin *1 15.0 15.0 15.0 15.0 15.0 15.0 titanium CR-95 *2 45.0 45.0 45.0 45.0 45.0 45.0 Fastgen blue NK *3 2. 3 2.3 2.3 2. 3 2. 3 2.3 xylene 8.0 8.0 9.0 8.0 8.0 Solvesso 100 *4 4.0 4'.0 4.0 440 4.0 n-butanol 7.0 7.0 7.0 7.0 7.0 Silicon KF-69 ~5 0.015 0.015 0.015 0 0.015 0.015 Baking cond.

*x 30 sec. 140 140 140 140 140 140 Film performance appearance *6 0 A- 0 gloss 95 93 91 94 88 pencil hardness*7 H-2H H F-H F H F_ weathering resis. 86 90 82 65 84 recoatability *8

A

gloss retention after 0-Meter Resin weight is weight 1500 hours expressed in Sunshine Weatherin terms of solid -26wherein *1 melamine resin, manufactured by Mitsui Toatu Kagaku K.K. non-volatile content *2 white pigment, manufactured by Ishihara Sangyo K.K.

*3 blue pigment, manufactured by Dainihon Ink K.K.

*4 mixed solvent, manufactured by Esso Standard Petrol.

Co.

surface conditioner, manufactured by Shinetsu Kagaku

K.K.

i *6 Finishing appearance was evaluated by visual observation on the followina standard: I very good 0 good fairly good X no good *7 maximum hardness no to be injured by Mitsubishi Uni pencil *8 A coated plate was over-baked at 160"C for 30 minutes and then applied by spraying with the respective coating composition and again baked at 120°C for minutes. (recoating of the same type of top-coat composition) Thereafter, the coating was cross-cut (2 mm width) by a razor and subjected to a peeling test with scotch tape. Number of peeled, 2 mm square pieces was determined and recoatability was evaluated according to the following criterion.

-27- Sno peeling (very good) 0 1 10 (good) A 11 30 (fairly good) X 31 and more(no good) Examples 19 to 23 and Comparative Examples 9 to 12 Using various resin varnishes obtained in Examples 3,5,7,9,10 and Comparative Examples 1 to 4 and isocyanate compound as a curing agent and following the prescriptions given in Table 3, blue color coating compositions were prepared. After 40 dilution, they were applied by spraying and the coatings were o a evaluated as in Example 11. The test results obtained are S° shown in Table 3.

ao SIn either case, the recoatability is greatly improved without being affected adversly on the weathering resistance of the coating.

a 4 I -28- 0 o 0 0 Co o 0 0 0 0 0 a i 0 00 Table 3 Example 19 20 21 22 23 Prescription polyester resin 3 50.0 7 50.0 9 50.0 alkyd resin 5 50.0 acrylic resin 10 50.0 isocyanate compound *9 10.2 10.2 10.5 10.5 11.0 Cellosolve acetate 10.0 10.0 10.0 10.0 10.0 Solvesso 100 26.0 26.0 26.0 26.0 26.0 Titanium CR-95 70.0 70.0 70.0 70.0 70.0 Fastgen blue NK 3.5 3.5 3.5 3.5 Modaflow *10 0.8 0.8 0.8 0.8 0.8 Baking cond.

°C x 30 min. 80 80 80 80 Film performance 0 0 0 A appearance 0 C gloss 95 96 95 93 pencil hardness F HB-F F-H H F-H weathering resis 90 81 85 93 recoatability 0 gloss retention after 2000 hours in Sunshine Weather- O-Meter *9 Sumidul N, aliphatic polyisocyanate, non-volatile cont.

manufactured by Sumitomo-Bayer Urethane surface conditioner, by Monsanto -29- ~_iCi _iY~ill I i osno,o A ,p Table 3 (continued) Com. Example 9 10 11 12 Prescription polyester resin 11 50.0 A 50.0 alkyd resin 12 50.0 acrylic resin 13 50.0 isocyanate compound *9 10.2 10.2 11.0 19.0 Cellosolve acetate 10.0 10.0 10.0 10.0 Solvesso 100 26.0 26.0 26.0 26.0 Titanium CR-95 70.0 70.0 70.0 70.0 Fastgen blue NK 3.5 3.5 3.5 Modaflow *10 0.8 0.8 0.8 0.8 Baking cond.

°C x 30 min. 80 80 80 Film performance appearance 0 gloss 90 92 87 88 pencil hardness F HB-F F-H HB-F weathering resis.

87 76 88 42 recoatability X X A gloss retention after 2000 hours in Sunshine Weather- O-Meter *9 Sumidul N, aliphatic polyisocyanate, non-volatile cont.

manufactured by Sumitomo-Bayer Urethane surface conditioner, by Monsanto .sF Synthetic Example 1 Into a reaction vessel fitted with heater, stirrer, reflux condenser, water separater, fractionating column and thermometer, were placed 19.4 parts of hexahydro phthalic anhydride, 22.6 parts of trimethylol propane, 26.5 parts of neopentyl glycol and 30.1 parts of 1,6-hexanediol and the mixture was heated. When the charged materials were melted and brought to the condition capable of being.stirred, stirring was commenced to do and temperature was raised to 210"C. From 210"C to 230"C, said temperature was increased at e..OO a constant speed in 2 hours and the formed water was removed out of the system during said heating. When reached to 230°C, S the mixture was maintained at the same temperature until the S resinous acid value of 1.0 and then allowed to cool.

After cooling, 83.1 parts of isophthalic acid were added and again heated to '-T0C. From 190°C to 210°C, said temperature was raised at a constant speed in 3 hours, during which time Sthe formed water was removed out of the system continuously.

When reached to 210°C, 3.2 parts of xylene were added and the reaction was switched to condensation in the presence of I solvent. At the stage when resinous acid value come to 20.0, the mixture was allowed to cool and then added with 75.9 parts of Cellosolve acetate to obtain an oil-free polyester resinous varnish A (ahereinafter called as base resin A).

Next, 28.7 parts of reactive silicon resin DC-3037 (Dow Corning Co.) and 0.38 part of TBT-100 (tetrabutyl tianate, condensation catalyst. Manufactured by Nihon Soda were -31-

L

_r r~i. 1 added and the mixture was heated and stirred. The reaction was continued at 140°C until the formed and recoverd methanol quantity reached to 75% of the theoretical amounts (which is the methanol quantity at the time when 100% of methoxy groups in the reactive silicon resin are reacted with hydroxyl groups of the polyester resin), and then the mixture was allowed to cool. After cooling, 5.8 parts of xylene and 13.6 parts of Cellosolve acetate were added to obtain a sili-con modified polyester resin varnish I. This varnish showed the characteristics of non-volatile content of 60.3% varnish viscosity (Gardner's o 0 viscosity, 25 0 C) of N-O and resinous acid value of 17.3.

Synthetic Example 2 Following the prescription shown in Table 4 and using a conventional method, coconut oil was subjected to esterexchange reaction and then condensation reaction was carried out as in Synthetic Example 1 until the resinous acid value of 20.0. (hereinafter called as base resin B) After cooling, the base resin was then subjected to silicon modification as in Synthetic Example 1 to obtain silicon modified alkyd resin varnish II. The characteristics of this varnish are shown in Table 4.

Synthetic Example 3 According to the prescriptions shown in Table 4, the similar condensations were carried out as in Synthetic Example 1 to the resinous acid value 40.0, and then allowed to cool to obtain base resin C. To the base resins, reactive silicon -32resin DC-3037 was added so as to give the weight ratio of base resin silicon resin (solid) 40 60, and silicon modification was carried out as in Synthetic Example 1, to obtain silicon modified polyester resin varnish III. The characteristics of this varnish are shown in Table 4.

Synthetic Example 4 Into a reaction vessel, were placed 45 parts of xylene and parts of Cellosolve acetate and the mixture was-heated to 130°C. To this, a mixed solution of 15 parts of styrene (ST), 42.2 parts of n-butyl methacrylate (n-BMA), 16.6 parts of lauryl methacrylate (LMA), 23.2 parts of 2-hydroxyethyl '°2o methacrylate (2HEMA), 3.0 parts of methacrylic acid (MAA), S 2.0 parts of t-butyl peroxy-2-ethylhexanoate and 0.3 part of laurylmercaptane was added at a constant speed in 3 hours.

After keep warming for 30 minutes, a mixed solution of parts of t-butyl peroxy 2-ethylhexanoate and 5 parts of xylene was added at a constant speed in 30 minutes and the reaction was continued at an elevated temperature for 2 hours and then allowed to cool (base resin After cooling, 17.6 parts of DC-3037 were added and the reaction was continued at 140°C while removing the formed methanol out of the system.

Sampling was made time by time. That is, the test sample was coated as thin film on glass plate and subjected to forced drying (130"C x 20 minutes). In the inspections made before and after drying, if the resins were thoroughly mixed together and clear coatings were observed, it was determined as final point of the reaction. At this point, the reaction mixture -33was allowed to cool. After cooling, the mixture was added with 34.2 parts of xylene to obtain a silicon modified acryl resin varnish IV. The characteristics of this varnish are shown in Table 4.

0 0 0

I,

a -34l I;~

Q

o 0 0o 0 I 15 Table 4 Example 1 2 3 4 Composition ST 19.4 hexahyd.phtha.anhyd. 19.4 19.4 19.4 n-BMA isophthalic acid 83.1 42.2 pentol 30.1 LMA 16.6 trimethylol propane 22.6 46.3 122.4 2 HEMA neopentylglycol 26.5 14.7 23.2 1,6-hexanediol 30.1 16.7 MAA coconut oil 43.2 isophthalic acid 83.1 83.1 trimellitic anhydride 16.0 OH value of base resin 112 112 500 100 acid value of base resin 20 20 40 Silicon modification name of base resin A B C D amount of resin(solid) 85 85 40 silicon resin DC-3037 DC-3037 DC-3037 DC-3037 amount of silicon res. 15 15 60 Varnish characteristics non-volatile content 60.3 59.4 61.4 50.1 varnish viscosity N-O K J X-Y resinous acid value 17.3 16.9 15.9 17.3 Name of varnish I II III IV Example 24 Using the silicon modified polyester resin varnish I obtained in Synthetic Example 1 and melamine resin as a curing agent and following the prescription given in Table 5, a blue color coating composition was prepared. To this composition, polyethyleneimine (Epomine SP-110, trade mark of Nihon Shokubai Kagaku) was added in the weight ratio of silicon modified polyester resin polyethylene imine- 99 1 (in solid). Thus obtained composition was diluted with a mixed i 10 solvent of Solvesso 150 (Esso Standard Petrol. Co.) xylene I butyl acetate methylisobutyl ketone 50/20/15/15, to viscosity of 23 seconds (Ford cup SPC-1 dull steel plate previously treated with zinc phosphate bath and applied with an intercoat was spray-coated with the abovesaid diluted composition and after standing for a defined period of time, baked at 140°C for 30 minutes. Thus obtained coating was evaluated as hereinafter stated and the test results were shown in Table Examples 25 to 30 and Comparative Examples 13 to 17 Using various silicon modified resin varnishes obtained in Synthetic Examples 1 to 4 and following the prescriptions shown in Table 5, blue color coating compositions were prepared, coated and evaluated as in Example 24. The test results are shown in Table -36dni, n a i j_ LIIL II~LLII--- L-^I1.o 0 Table Example 24 25 26 silicon modif. polyester resin I 42.0 III 42.0 silicon modif. alkyd resin II 42.0 silicon modif. acryl resin melamine resin U-20SE *1 18.0 18.0 18.0 isocyanate compound Sumidul N *2 titanium CR-95 *3 70.0 70.0 70.0 Fastgen blue NK *4 3.5 3'5 Cellosolve acetate 10.0 10.0 10.0 Solvesso 100 26.0 26.0 26.0 Modaflow *5 0.8 0.8 0.8 Epomine *6 0.42 0.42 Polyethyleneimine 15 T *7 0.42 solid weight ratio of silicon modif. resin/ 99/1 99/1 99/1 polyethyleneimine baking condition "C x 30 min. 140 140 140 Film performance finish, appearance *8 0Q gloss 93 96 94 pencil hardness *9 F-H F H-2H weathering resistance 85 76 88 recoatability *10 resinous weights are solid weight gloss retention after 1500 hours in Sunshine Weather- O-Meter -37- \<9 0 o 9 0 9 o o9 a a 1 9 *9 s O 0 99 Table 5 (continued) Example 27 28 29 silicon modif. polyester resin I 42.0 I 42.0 silicon modif. alkyd resin silicon modif. acryl resin IV 42.0 melamine resin U-20SE *1 18.0 18.0 18.0 isocyanate compound Sumidul N *2 titanium CR-95 *3 70.0 70.0 70.0 Fastgen blue NK *4 3.5 3.5 Cellosolve acetate 10.0 10.0 10.0 Solvesso 100 26.0 26.0 26.0 Modaflow *5 0.8 0.8 0.8 Epomine *6 0.042 Polyethyleneimine 15 T *7 0.42 1.75 solid weight ratio of silicon modif. resin/ 99/1 99.9/0.1 96/4 polyethyleneimine baking condition °C x 30 min. 140 140 140 Film performance finish, appearance *8 0 0 0 gloss 92 93 pencil hardness *9 H F-H F weathering resistance 92 86 recoatability *10 0 0 resinous weights are solid weight gloss retention after 1500 hours in Sunshine Weather- O-Meter -38-

I

I

I

C4640 4 4 4 66 4 0 4 0~ 44 6 C 10 4 0 6 4 41 *6 4o 0

I

4 Cc .6 C 1206 4.

Table 5 (continued) Example 30 Comp.13 Comp.14 silicon modif. polyester resin 1 50.0 1 42.0 silicon modif. alkyd resin 11 42.0 silicon modif. acryl resin melamine resin UJ-20SE *1 18.0 18.0 isocyanate compound Sumidul N *2 10.2 titanium CR-95 *3 70.0 70.0 70.0 Fastgen blue NK *4 3. 5 3. 5 Cellosolve acetate 10.0 10.0 10.0 Solvesso 100 2 G. 0 26.0 26.0 Modaflow *5 0.8 0.8 0.8 Epomine *6 0.51 Polyethyleneimine 15 T *7 solid weight ratio of silicon modif. resin/ 99/1 polyethyleneimine baking condition 'C x. 30 min. 80 140 140 Film performance finish, appearance *8 0 0 gloss 92 90 pencil hardness *9 F-H F-H F weathering resistance **94 86 71 recoatability *10 x X 1, resinous weights are solid weight *gloss retention after 1500 hours in 0-Meter Sunshine Weather- -39-

I

Example Comp. 15 Comp.16 Comp.17 silicon modif. polyester resin III 42.0 I 50.0 silicon modif. alkyd resin silicon modif. acryl resin III 42.0 melamine resin U-20SE *1 18.0 18.0 isocyanate compound Sumidul N *2 10.2 titanium CR-95 *3 70.0 70.0 70.0 Fastgen blue NK *4 3.5 3.5 Cellosolve acetate 10.0 10.0 10.0 Solvesso 100 26.0 26.0 26.0 Modaflow *5 0.8 0.8 0.8 Epomine *6 Polyethyleneimine 15 T *7 solid weight ratio of silicon modif. resin/ polyethyleneimine baking condition 'C x 30 min. 140 140 Film performance finish, appearance *8 0 Q 0 gloss 91 86 91 pencil hardness *9 H-2H H F weathering resistance 86 90 recoatability *10 X X 6 resinous weights are solid weight gloss ietention after 1500 hours in Sunshine Weather- O-Meter

V

wherein *1 melamine resin, manufactured by Mitsui Toatu Kagaku K.K. non-volatile content *2 aliphatic polyisocyanate, non-volatile manufactured by Sumitomo Bayer Urethane *3 white pigment, manufactured by Ishihara Sangyo K.K.

*4 blue pigment, manufactured by Dainihon Ink K.K.

surface conditioner, manufactured by Monsanto *6 Polyethyleneimine compound, molecular weight about 1000 manufactured by Nihon Shokubai Kagaku Kogyo *7 Polyethyleneimine compound, viscosity 1000 2000 a. cps, manufactured by Sogo Yakko K.K.

*8 Finishing appearance was evaluated by visual observation on the following standard very good Q good A fairly good X no good *9 maximum hardness no to be injured by Mitsubishi Uni pencil A coated plate was over-baked at 160°C for 30 minutes and then applied by spraying with the respective coating composition and again baked at 120°C for minutes.(recoating of the same type of top-coat composition) Thereafter, the coating was cross-cut (2 mm width) by a razor and subjected to a peeling test with scotch -41- L I n I lir- tape. Number of peeled, 2 mm square pieces was determined and recoatability was evaluated according to the following criterion.

ono peeling (very good) 0 1 10 (good) A 11 30 (fairly good) X 31 and more(no good) From these test results, it is clear that in either case of melamine and isocyanate curing agents, the recoatability is greatly improved by the addition of polyalkyleneimine without S* being affected adversly on the weathering resistance of the S coating.

-42-

Claims (2)

1. A coating composition comprising a silicon modified resin having a number average molecular weight of between 500 and 2000 and which is obtained by subjecting a base resin having both hydroxyl and carboxyl groups to a silicon modification with an organopolysiloxane resin represented by the formula: R Si(OR') O 4 n n m 4 n m 2 wherein R is a monovalent organic group attached to Si through C-Si bonding; R' is hydrogen, C 1 to C 20 alkyl or aryl group; and n and m each represents a real number of 4 or less, proided that n m is less than or equal to 4, and a polyethyleneimine of the formula: -CH -CH 2 2 0R n S0r NH 2 CH 2 CH 2 CH2-NH---- CH 2 I CH2 CIA 2 -N- S 25 wherein R is hydrogen, substituted or unsubstituted C 1 to alkyl or aryl group; n is an integer from 3 to 2000; x is an integer from 0 to 1000; and y is an integer from 3 to 2000, i wherein the weight ratio of is 95 to 99.99/5 to 0.01.

2. A coating composition as defined in claim 1 and substantially as herein described with reference to Examples 24 to 30 and comparative Examples 13 to 17. DATED 3rd day of April, 1990 NIPPON PAINT LTD, By their Patent Attorney GRIFFITH HACK CO. 6207S/as 43 T