JPS63301216A - Two-pack urethane resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. having an excellent mar resistance by, blending a specific polyester polyol with an isocyanate compd(s). or a prepolymer with terminal NCO groups prepd, by reacting an isocyanate compd(s). with an active hydrogen compd. CONSTITUTION:A dicarboxylic acid (a) such as phthalic anhydride is reacted with a glycol (b) such as 3-methyl-1,5-pentanediol and/or a polyol with 3 or more OH groups (c) such as trimethylolpropane to prepare a polyester polyol (A) having an ester group concn. of at least 0.004mol./g and pref. an average MW of 500-3,000 and a hydroxyl group value of 90-560. Subsequently, the component A is admixed with an isocyanate compd(s). such as 2,4- and/or 2,6- tolylene diisocyanate or a prepolymer with terminal NCO groups prepd. by reacting such an isocyanate compd(s). with an active hydrogen compd. such as trimethylolpropane (B) at an NCO to OH ratio of 0.2-3.0.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a two-component urethane resin composition with excellent scratch resistance.

Conventional technology Urethane resin has excellent toughness and chemical resistance.

Paints and printing inks because of their adhesion, abrasion resistance, and gloss.

Widely used in adhesives, etc. However, its scratch resistance is not satisfactory; for example, wooden furniture coated with urethane paint may be scratched during transportation and lose its commercial value. Highly UV-curable paints with excellent scratch resistance have been developed, but they are not widely used because they have drawbacks in workability, physical properties, etc., and require ultraviolet irradiation equipment.

Problems to be Solved by the Invention An object of the present invention is to provide a urethane resin composition that provides a coating film with excellent scratch resistance.

Means for Solving the Problems The present inventors have conducted intensive studies on urethane resin compositions that provide coating films with excellent scratch resistance. Using a specific polyester polyol, the present inventors have combined this with an isocyanate compound or with an active hydrogen compound. It has been found that a composition obtained by combining a prepolymer having an NCO group at the terminal obtained by the reaction of the above has a high hardness of the coating film and excellent scratch resistance.Based on these findings, the present invention has been completed. reached.

That is, in the present invention, the ester group concentration obtained by reacting a (+) dicarboxylic acid with a glycol or/and a polyol having at least three OH groups is 0.00.
The present invention relates to a two-component urethane resin composition comprising a polyester polyol having a content of 4 mol/g or more and (2) an isocyanate compound or a prepolymer having an NCO group at the end obtained by reacting it with an active hydrogen compound.

The polyester polyol used in the present invention contains a dicarboxylic acid and a glycol or/and at least three OH
It is obtained by reacting a polyol having a group.

As the dicarboxylic acid used for producing this polyester polyol, for example, maleic acid is used.

Unsaturated dicarboxylic acids such as fumaric acid and their anhydrides, saturated dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid.

Examples include aromatic or ring dicarboxylic acids such as hexahydrophthalic acid. Among the above dicarboxylic acids, 2
The length of the main chain between the carboxyl groups is preferably 4 or less, particularly 3 or less in terms of carbon number.

Examples of glycol include ethylene glycol, 1
．． 2-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2゜3-butylene glycol, l,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, Aliphatic glycols such as tripropylene glycol, decamethylene glycol, 1,5-bentanediol, 2,4,4-trimethyl-1,3-bentanediol, 3-methyl-1,5-bentanediol, e.g. Examples include ring group glycols such as cyclohexanediol, 4-cyclohexanediol, and hydrogenated bisphenol A.

Among the above glycols, the length of the main chain between two OH groups is preferably 4 or less, particularly 3 or less in terms of carbon number.

As the polyol having at least 3 OH groups,
For example, glycerin, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, tri(2-hydroxyethyl)amide.

Examples include triols such as pentaerythritol, sorbitol, and sucrose.

From the viewpoint of scratch resistance, the ester group concentration of this polyester polyol is about 0.004 mol/g or more, especially about 0.0
05 to 0.015 mol/g is preferable, and its average molecular weight is 500 to 3000. The hydroxyl value is about 90 to 560.

Among the isocyanate compounds used in the present invention or prepolymers having NCO groups at the terminals obtained by reacting them with active hydrogen compounds, the isocyanate compounds include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, etc. Pentamethylene diisocyanate, 1
．． 2-butylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate.

Aliphatic diisocyanates such as 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diucyanatomethylcabroate, e.g. 1,3-cyclo Pentane diisocyanate, ■.

4-cyclohexane diisocyanate, 1.3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-1 rimedyl isocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), methyl 2,4-yl clohexane Diisocyanate, cycloalkylene diisocyanate such as methyl 2,6-cyclohexane diisocyanate, ■, 4-bis(isocyanatomethyl)cyclohexane, ■, 3-bis(isocyanatomethyl)cyclohexane, such as m-phenylene diisocyanate, p-phenylene diisocyanate , 4.4-u phenyl diisocyanate.

1.5-naphthalene diisocyanate, 4.4'-diphenylmethane diisocyanate, 2,4- or 2.6
- tolylene diisocyanate or mixtures thereof; 4.
4'-) Aromatic diisonoanates such as luidine diisocyanate, cyanidinone diisocyanate, 4,4'-diphenylethernoisocyanate, I, 3- or 1,4-quinrylene diisocyanate or mixtures thereof, ω, ω'-diisocyanate 1,4-diethylbenzene 11゜3- or 1,4-bis(α, α-
Aroaliphatic noisocyanates such as dimethyl isocyanate (methyl)benzene, e.g. triphenylmethane-
4゜4',4''-1-liisocyanate, 1,3.5-
Triisocyanates such as triisocyanate benzene, 2,4.6-triisocyanate toluene, 4°4'
Examples include tetraisocyanates such as -diphenyldimethylmethane-2,2',5,5'-tetraisocyanate, polymerized polyisocyanates such as trilenenoisocyanate dimer and trimer, and polyphenylpolymethylene polyisocyanate. These can be used alone or as a mixture of two or more.

Examples of active hydrogen compounds used in the production of prepolymers having NCO groups at their terminals include ethylene glycol, 2-propylene glycol, and 2-propylene glycol.

! , 3-propylene glycol, l, 3-butylene glycol, ■, 4-butylene glycol, 2.1-butylene glycol, l, 6-hexanediol.

Neopentyl glycol, l,4-cyclohexaneol, ■,4-cyclohexane dimetatool.

Hydrogenated bisphenol A, diethylene glycol, triethylene glycol, dipropylene glycol.

Glycols such as tripropylene glycol, 1,3-xylylene glycol, 1,4-xylylene glycol, 1,5-bentanediol, 2,4,4-)dimethyl-1,3-pentanediol, such as glycerin,
Trimethylolpropane, trimethylolethane, 1,
2.6-hexanetriol, pentaerythritol,
Low molecular weight polyols such as sorbitol, for example molecular weight 300-to, ooo.

Examples include hydroxyl group-containing compounds such as polyether polyols, polyester polyols, and polyether ester polyols having 2 to 4 functional groups.

Examples of polyether polyols include those obtained by ring-opening addition polymerization of ethylene oxide, propylene oxide, or a mixture thereof using ethylene glycol, propylene glycol, glycerin, pentaerythritol, or the like as an initiator; Examples include polytetramethylene ether glycol obtained by ring-opening polymerization.

Examples of polyester polyols include maleic acid, fumaric acid, succinic acid, adipic acid, and sepacic acid.

It is obtained by a condensation reaction between a di- or tri-basic acid such as azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, or trimellitic acid and a di- to tetrahydric alcohol.

Examples of di- to tetrahydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol 1 dipropylene glycol, 1
．． 3-butylene glycol, I,4-butylene glycol, l,5-bentanediol.

1.6-hexanediol, neopentyl glycol,
decamethylene glycol, 2,4.4-)rifutyl-1
, 3-bentanediol, cyclohexanediol, cyclohexanedimethanol, xylylene glycol, hydroquinone bis(hydroxyethyl ether), hydrogenated bisphenol A, trimethylolpropane, glycerin, I, 2,6-hexanetriol, pentaerythritol, castor oil, etc. can be given. For example, coconut oil fatty acids, linseed oil fatty acids, soybean oil fatty acids, cottonseed oil fatty acids,
Tung oil fatty acids.

A higher fatty acid such as Himashiura fatty acid may be blended into the acid component to form a fully modified polyester polyol.

Examples of polyether ester diols include those obtained by subjecting polyether polyol to a polyesterification reaction with a polybasic acid as a raw material, as well as those obtained by a ring-opening copolymerization reaction of an epoxide compound and an acid anhydride. Compounds having both polyether polyester segments in one molecule can be mentioned. Polybutane Enfall. Polyisoprene diol, castor oil, etc. can also be used as polyols.

These active hydrogen compounds can be used alone or as a mixture of two or more.

The reaction between an isocyanate compound and an active hydrogen compound can be carried out without a solvent, but usually, for example, ethyl acetate, butyl acetate, cellosolve acetate, toluene, xylene,
Methyl ethyl ketone, methyl isobutyl ketone, acetone, tetrahydrofuran.

It is carried out in a solvent without active hydrogen, such as dioxane. The reaction temperature is about 10-150°C, preferably about 40°C.
~90°C. If the reaction is slow, a catalyst that promotes the usual urethanization reaction, such as a metal compound, an organometallic compound, an organic amine compound, etc., may be added.

Further, after the reaction between the isocyanate compound and the active hydrogen compound is completed, unreacted isocyanate compound may be removed by extraction or distillation.

Among the prepolymers having isocyanate groups at the ends obtained in this way, the isocyanate group content (per solid content) is preferably 3 to 30% from the viewpoint of scratch resistance.
Furthermore, 6 to 20% is more preferable. in particular,
adduct of diisocyanate and trimethylolpropane,
Most preferred are triuric isocyanates.

The prepolymer or isocyanate compound thus obtained and the polyester polyol are mixed to form a urethane resin composition, and the mixing ratio of the two is such that the ratio of isocyanate groups to hydroxyl groups is 0.2 to 3.0. Preferably 0.
5 to 2.0.

When applying the composition obtained in this way, it is possible to use it without a solvent, but it is generally preferable to dissolve it in an organic solvent that does not contain active hydrogen.

Examples of organic solvents without active hydrogen include esters such as ethyl acetate, butyl acetate, and cellosolve acetate, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, toluene,
Examples include aromatic hydrocarbons such as xylene, and ethers such as tetrahydrofuran and dioxane. Ketones are particularly preferred because they not only easily dissolve the composition but also have the effect of lengthening the pot life.

When carrying out the present invention, pigments, dyes, leveling agents, anti-sagging agents, antifoaming agents, catalysts, stabilizers, anti-settling agents, etc. may be used in combination as necessary. In this case, these additives are dispersed or mixed in the polyester polyol in advance.

The composition thus obtained is useful as a scratch-resistant paint, adhesive, etc., and can be applied by a conventional method such as a spray gun, roll coater, flow coater, etc.

As a base material, for example, 0 wood, 1 glass, 1 ceramic,
Iron, copper, aluminum, stainless steel, slate, flexible board, perlite board.

It may be asbestos slate, plastic or a composite material thereof. If the substrate coated with the composition is left at room temperature, crosslinking will occur due to the reaction between isocyanate groups and hydroxyl groups, resulting in a tough coating.

If crosslinking is desired to be accelerated, heating may be performed to about 60 to 80°C.

The resulting coating film has a good appearance with no foaming, and has high hardness and excellent scratch resistance, as well as impact resistance, heat resistance,
It has good water resistance, moisture resistance, and chemical resistance, and is used, for example, as a paint or adhesive for wooden furniture.

Effects of the Invention When the composition of the present invention is applied to, for example, wooden furniture, it will not be damaged even when transported over long distances, so it can be particularly advantageously used in fields that require transportation.

The present invention will be explained in more detail with reference to Examples below.

In the examples, parts indicate parts by weight, and % indicates weight %.

Example! 319.7 parts of 3-methyl-1,5-bentanediol,
78.9 parts of phthalic anhydride and 0.1 part of butyltinnolaurate were placed in a reaction vessel, heated to 220°C, nitrogen gas blown in, and reacted while distilling off the condensed water produced, until the acid value reached 18.0. When it becomes phthalic anhydride 3
57.8 parts were charged, and from the time when the reaction temperature reached 170°C, the reaction was carried out for 1 hour to obtain terminal C00I- with an acid value of 177.0.
, an esterified product having one group was obtained. To this reaction mixture were added 244.3 parts of trimethylolpropane and 0.1 part of diptyltin laurate, and the reaction was similarly carried out while distilling off the water of condensation to obtain an acid value of 9.9. Hydroxyl value +03.0. Average molecular weight: 2484. A polyester polyol having an ester group concentration of 0.0073 mol/g was obtained. This polyol was dissolved in butyl acetate to form a solution with a solid content of 50%.

On the other hand, tolylene diisocyanate (2,4 body 80%, 2
．． 6 bodies 20%) 261 parts trimethylolpropane 44
, 7 parts at 75-80°C for 2 hours, unreacted tolylene diisocyanate was removed by thin film distillation, and dissolved in ethyl acetate to obtain a solution with a solid content of 75% and an isocyanate group content I of 3.0%. A prepolymer solution was obtained.

Mix 1,089 parts of the above polyester polyol solution and 323 parts of the above prepolymer solution, apply it to a thickness of 50μ on an iron phosphate treated iron plate using an air spray gun, and leave it at room temperature for one day to completely remove the mixture. A dry and tough coating film was obtained. The physical properties of this coating film were as follows.

Pencil hardness 2 parts adhesion 100/100 Erichsen extrusion test 8ml 11 impact resistance (Dupont type)
l/2”xlooOgx40cm bending
2mm Scratch Resistance 7 Pass 0 Rub the paint film with steel wool and check for scratches. Pass if there are no scratches.

Example 2 552.6 parts of succinic acid, 152.5 parts of ethylene glycol, and 47 parts of trimethylolpropane were prepared in the same manner as in Example 1.
0.9 part was reacted to give an acid value of 5.5. Hydroxyl value 334.1
．． Average molecular weight 826. A polyester polyol having an ester group concentration of 0.0091 mol/g was obtained. This polyol was dissolved in butyl acetate to form a solution with a solid content of 50%.

On the other hand, 100 parts of 2,4-tolylene diisocyanate was dissolved in 100 parts of butyl acetate, and 0.2 parts of potassium acetate was added to carry out a trimerization reaction, resulting in a solution containing a maximum of 7.6% of isocyanate groups.
A polyisocyanate solution was obtained.

336 parts of the above polyester polyol resin solution and 550 parts of the above polyisonoanate solution were mixed and spray coated onto an iron phosphate treated iron plate to a thickness of 50μ, and then left at room temperature for 1 day to completely dry and strengthen. A coating film was obtained. The physical properties of this coating film were as follows.

Pencil hardness 3-part adhesion 100/ 100 Erichsen extrusion test 8mm Impact resistance (Dupont type) I/ 2” x 500g
x 40 cm bending 4 mm Scratch resistance Passing Example 3 469.4 parts of adipic acid was prepared in the same manner as in Example I.

646.4 parts of trimethylolpropane was reacted, and the acid value was 3.8. Hydroxyl value 446.1. A polyester polyol having an average molecular weight of 623° and an ester group concentration of 0.0064 mol/g was obtained. This polyol was dissolved in butyl acetate to form a solution with a solid content of 50%.

250 parts of this polyester solution and 550 parts of the polyisocyanate solution of Example 2 were mixed, spray-coated onto an iron phosphate-treated iron plate to a thickness of 50μ, and then heated to room temperature for 1 hour.
A strong coating film was obtained by leaving it in the sun and completely drying it. The physical properties of this coating film were as follows.

Claims (1)

[Claims] (1) a polyester polyol with an ester group concentration of 0.004 mol/g or more obtained by reacting a dicarboxylic acid with a glycol or/and a polyol having at least three OH groups; and (2) an isocyanate compound or an active compound thereof. A two-part urethane resin composition containing a prepolymer having an NCO group at the end obtained by reaction with a hydrogen compound.