JPS6386762A - Scratch-resistant coating compound composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition suitable for furniture, automobiles, etc., having improved adhesiveness to the surface of materials to be coated and excellent resistance to scratching, by blending a polyester polyol with a polyisocyanate in a specific ratio. CONSTITUTION:The aimed composition which is obtained by blending (A) a polyester polyol having 30-70wt% (in acid raw material) aliphatic dibasic acid, 2.5-3.5 average hydroxyl groups based on one molecule, 500-1,500 number-average molecular weight, further preferably 100-250 hydroxyl number and 0.2-2.0 ethereal oxygen content with (B) a polyisocyanate in an equivalvent ratio of hydroxyl group and isocyanate group of 0.5-2.0:1 and (C) a tin type urethanized catalyst as essential components, provides a coating film with flexibility and toughness, is slightly scratched by absorbing external force and restores the coating film to the original form even if the film is scratched.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a coating composition with excellent scratch resistance. Specifically, it is a coating t1 target material that exhibits excellent scratch resistance when coated on materials such as wood, plastic, etc., or on these objects to form a film.

[Conventional Technology J] At present, various painted products are easily scratched and scratched during each process after painting or during transportation, and are easily scratched. It is often necessary to repair or repaint in severe cases, and the losses incurred due to these are enormous, and by solving this problem, it is possible to prevent losses in all fields. There is a strong demand for the development of scratch-resistant coated materials suitable for such purposes. A scratch-resistant material suitable for such purposes has excellent adhesion to the surface of the object to be coated, and has mechanical properties and resistance suitable for various uses as a coating film, such as furniture, stereos, automobiles, building materials, f: A equipment, etc. Requires coating film properties such as chemical properties.

[Point m during which the invention attempts to solve the problem] Conventionally, as a means to solve this object, various resins have been studied based on the policy of increasing the scratch resistance by hardening the coating film. Ta. However, by making it hard, it becomes less susceptible to scratches, but - when it is stored, it tends to leave scratches, and the hardness of the film also tends to cause cracks, so it must be applied at a thickness thinner than the normal coating thickness. Therefore, there is a drawback that the general coating film performance as a protective film is inferior. On the other hand, research on the abrasion resistance of resins from a structural perspective has also progressed, and specifically studies have been carried out on acrylic resins, polyurethane resins, polyester resins, epoxy resins, ethylene-vinegar vinyl, etc., but the above drawbacks have been fundamentally investigated. could not be resolved.

[Means for Solving the Problems] The present inventors have discovered that the film created by the polyaddition of polyester polyol and polyisocyanate has a structure close to rubber elasticity, so the film itself is flexible and strong.

As a result of research based on the knowledge that it has both good properties and good abrasion resistance, we found that rather than using the hardness of the film to achieve scratch resistance, we instead created a film with flexibility and toughness to improve scratch resistance. The inventors have now invented a coating composition that has excellent scratch resistance and provides a film that is resistant to scratches by absorbing the above-mentioned substances, and even if it is scratched, it can be restored to its original state.

That is, 1. In the present invention, 30 to 70% by weight of the acid raw material is an aliphatic dibasic acid, has an average of 2.5 to 3.5 hydroxyl groups per molecule, and has a number average molecular weight of 500 to 1,500.
The polyester polyol (A) 4 polyisocyanate (B) and the tin-based urethane catalyst (C) are essential components, and the ratio of the polyester polyol (A) to the polyisocyanate (B) is the equivalent of hydroxyl groups and isocyanate groups. The present invention provides a scratch-resistant coating composition having a ratio in the range of 0.5 to 2.0:1.

The polyester polyol (A) used in the present invention contains 30 to 70% by weight of aliphatic dibasic acid in the acid raw material, has an average of 2.5 to 3.5 hydroxyl groups per molecule, and has a number average The molecular weight is 500 to 1.500. If the aliphatic dibasic acid is less than 30% by weight in the acid raw material, the molecular chain of the polyester polyol will be too rigid and the film will have poor flexibility, and if it exceeds 70% by weight, the hardness of the film will decrease and it is not practical. If the number of hydroxyl groups per molecule is less than 2.5, the crosslinking density of the film is low and the elastic restoring force against scratches is poor, and if the number of hydroxyl groups is more than 3.5, the film has poor flexibility.

Furthermore, if the number average molecular weight is less than 500, the durability of the film will not be sufficient, and if it exceeds 1,500, the flexibility of the film will be poor.

#Raw materials that can be used in the present invention include phthalic acid, isophthalic acid, terephthalic acid, dimethyl terephthalate, tetrahydrophthalic acid, hemi7hydric acid, maleic acid, fumaric acid, succinic acid, adipic acid, sebacic acid, and dimer acid. ,
Dibasic acids such as trimery/ ) acid, he-/ ) acid, dodecanniic acid, or their acid anhydrides, as well as benzoic acid, methylbenzoic acid, p-tert-butylbenzoic acid, etc. can be used. As polyol components, ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, 1,4-butanediol, 1.
3-butanediol, 1. B-hexanediol, glycerine, dipropylene glycol, trimethylolethane, trimethylolpropane, 2,2.4-)riftyl-1,3-bentanediol, pentaerythritol, tris-2-hydroxyethyl isocyanurate, etc. can be used.

The polyester polyol used in the present invention can be produced by a conventional method. That is, the acid and polyol raw materials are heated and stirred at 150 DEG to 250 DEG C. under nitrogen, for example, and condensation is allowed to proceed until a suitable acid value and viscosity are achieved, followed by cooling.

The polyisocyanate (B), which is another component constituting the coating resin composition of the present invention, refers to 1.8-hexamethylene diisocyanate, 1. B-octamethylene diisocyanate, alkylene diisocyanates such as 1,2-dodecamethylene diisocyanate or 2,2,4-)limethylhexamethylene diisocyanate,
3.3'-diisocyanate dipropyl ether, 3-
Methyl isocyanate-3,5,5-)limethylcyclohexyl isocyanate, cyclopentylene-1,3-
Diisocyanates, cyclohexylene-1,4-diisocyanate, methyl-2,6-diisocyanate caproate, bis(2-isocyanatoethyl) fumarate, 4-methyl-1,3-diisocyanate cyclohexane, transvinylene diisocyanate and similar unsaturations Isocyanate; 4,4'-methylenebis(cyclohexyl isocyanate), methane diisocyanate, N,N',N'-)lis(6-indianatehexamethyl)bularet or bis(2-isocyanateethyl)carbonate and similar diisocyanates, etc. aliphatic or cycloaliphatic polyisocyanates; toluene diisocyanate, xylylene diisocyanate, dianisidine diisocyanate, 4,4'-diphenylmethane diisocyanate, l-ethoxy-2,4-diisocyanatebenzene, 1-chloro-2,4-diisocyanatebenzene , tris(4-isocyanatophenyl)methane, naphthalene diisocyanate, phleolein diisocyanate or 4,4′-biphenyl diisocyanate;
Phenyl diisocyanate, 3,3'-dimethyl-4
, 4'-biphenyl diisocyanate, p-isocyanate benzyl isocyanate, tetrachloro-1,3-
There are phenylene diisocyanates, etc., and one type or a mixture of two or more of these may be used, and isocyanate-terminated prepolymers which are reaction products of the above various polyisocyanates and low molecular weight polyhydroxy compounds or polyamine compounds can also be used. .

What is the tin-based urethanization catalyst (C) in the present invention?

For example, inorganic tin salt compounds such as tin chloride, stannic chloride, tin nitrate, tin sulfate, tin hydroxide, tin oxide, and tetra-n-
Butyltin, n-butyltin trichloride, di-n-butyltin dichloride, dimethyltin dichloride, trimethyltin hydroxide, dibutyltin dilaurate, dibutyltin di-2-ethylhexoate, dibutyltin diacetate, dibutyltin malate, Examples include organic tin salt compounds such as dibutyltin fumarate, but organic compounds are generally preferred because they have higher catalytic activity and excellent solubility in organic solvents.

In preparing the coating composition of the present invention, the ratio of polyester polyol (A) to polyisocyanate CB) is such that the equivalent ratio of hydroxyl groups to isocyanate groups is 0.5 to 2.0.
If the equivalent ratio of hydroxyl groups is less than 0.5, the amount of polyisocyanate (B) becomes excessive and side reactions between the polyisocyanates tend to occur, resulting in poor flexibility of the film.

If it exceeds 2.0, many hydroxyl groups in the polyester polyol (A) component remain, resulting in poor drying properties and durability of the film.

The film with excellent scratch resistance according to the present invention is preferably a rubber elastic resin with an elongation at break of 150% or more, and a film thickness of 201 or more, preferably 3
It is desirable that it be applied practically at 0H or higher.

In order to sufficiently exhibit the scratch resistance according to the present invention, the hydroxyl value of the polyester polyol (A) component constituting the present invention is preferably in the range of 100 to 250. If the hydroxyl value is less than 100, the crosslinking density of the film is low. However, the film strength is not sufficient, and if it exceeds 250, the crosslinking density increases and it becomes brittle.

Furthermore, in order to sufficiently exhibit the scratch resistance according to the present invention, the ether oxygen content in the polyester polyol (A) is preferably within the range of 0.2 to 2.0%. If it is less than 0.2%, the contribution of the polyether molecular chains to the entire polyester polyol is small, resulting in poor flexibility of the film.

If it exceeds 2.0%, the film tends to soften, which is not preferable.

When forming a film on the object to be coated with the coating composition of the present invention, dry at room temperature or at 50°C to 110°C, preferably at 8°C.
Forced drying at 0 to 100°C is acceptable, and the coating composition of the present invention can contain various inorganic and organic pigments.
Furthermore, additives such as slip agents can be added.

[Effects of the Invention] The coating composition of the present invention has the characteristic that even if the coating film obtained has rubber elasticity and is scratched by external force, the scratches can be restored to their original state due to the elastic recovery power. This is thought to be due to the elasticity of the non-uniform structure in the coating film (entropic elasticity of the soft segment and energy elasticity of the hard segment). In addition to these features, it has excellent adhesion to wood, plastic, etc., as well as mechanical properties such as hardness, impact resistance, and flexibility, chemical resistance,
It also has excellent durability such as stain resistance and weather resistance.
Since the present invention has such characteristics, by coating various objects with the present invention, it is possible to prevent losses caused by conventional repairs and repainting due to scratches.

Next, reference examples and examples of the present invention will be shown, but the present invention is not limited thereto.

Reference Example 1 35.2 parts of 1.8-hexanediol, 5.8 parts of glycerin, 7 parts of diethylene glycol, 50.0 parts of adipic acid, and 2.3 parts of phthalic anhydride in a four-loaf flask equipped with a stirrer and a thermometer. was charged, and the dehydration condensation reaction was advanced to an acid value of 5.5, with a hydroxyl value of 120 (solid content n) and a non-volatile content of 80.
% acetic acid solution.

Reference Example 2 In the same apparatus as Reference Example 1, 8.0 parts of ethylene glycol,
Dipropylene glycol 8.0 parts, trimethylolethane 13.3 parts, isophthalic acid 24.7 parts, cepatic acid 4 parts
0.0 part was charged and reacted, acid value 5.0, hydroxyl value (solid content equivalent) 200, non-volatile content 80% (acetic acid ethyl solution)
A resin liquid was obtained.

Reference Example 3 Neopentyl glycol 32.
8 parts of diethylene glycol, 6.7 parts of diethylene glycol, 7.0 parts of trimethylolpropane, 13.5 parts of phthalic anhydride, and 940.0 parts of adipid were reacted to give an acid value of 4.5. Hydroxyl value (solid content) 120, non-volatile content 75% (xylene, N
A resin liquid (IBK solution) was obtained.

Reference Example 4 Using the same equipment as Reference Example 1, 30.2 parts of ethylene glycol, 4.5 parts of trimethylolethane, and 55 parts of phthalic anhydride were added.
3 parts of adipic acid and 90 parts of adipic acid were reacted to obtain a resin liquid having an acid value of 3.5, a hydroxyl value (in terms of solid content) of 135, and a non-volatile content of 80% (ethyl acetate).

Reference example 5 13.0 parts of 1.8-hexanediol, 31 parts of glycerin
．． 1 part, adipine 1% 730.0 parts, phthalic anhydride 28
．． 0 part was reacted and the acid value was 4.0. Hydroxyl value (solid content conversion)
300, and a resin liquid with a nonvolatile content of 80% (ethyl acetate solution) was obtained.

Reference example 6 Dipropylene glycol 38.7 parts, glycerin 109
9 parts, 20.4 parts of phthalic anhydride, and 930.0 parts of adipine were reacted to obtain an acid value of 760 and a hydroxyl value (solid content conversion 'B) of 1G.
+), non-volatile content 80% (xylene, NIBK solution)
A resin liquid was obtained.

Examples 1 to 3 and Comparative Examples 1 to 4 HDI-TMP adduct polyisocyanate (Parnock DH-950, non-volatile content 75%,
An equivalent amount of a curing agent (manufactured by Effective NGO Ingredients 12/5) was blended, dibutyltin dilaurate was added, and the mixture was coated on a glass plate.

The results are shown in Table 1.

Test condition Curing conditions: Dry for 7 days at a temperature of 20°C and a humidity of 70±5%.

Scratch resistance: A coating film applied to a glass plate under the above curing conditions was scratched with a scratch hardness meter (load: 80 g), and judged based on the state of restoration of the scratch.

O...I'll be back soon.

Δ...It will not return completely.

×...It doesn't come back at all.

Alkali resistance: Soaked in 5% sodium hydroxide solution for 10 days.

Acid resistance: Soaked in 5% sulfuric acid solution for 10 days.

As can be seen from these results, the coating film obtained from the coating composition of the present invention is tough and has excellent scratch resistance.

Claims (3)

[Claims] (1) 30 to 70% by weight of the acid raw material is an aliphatic dibasic acid, has an average of 2.5 to 3.5 hydroxyl groups per molecule, and has a number average molecular weight of 500 to 1,500. Polyester polyol (A), polyisocyanate (B), and tin-based urethanization catalyst (C) are essential components, and the ratio of polyester polyol (A) to polyisocyanate (B) is such that the equivalent ratio of hydroxyl groups to isocyanate groups is 0. 5～
A scratch resistant coating composition having a ratio such that the ratio is in the range of 2.0:1. (2) The hydroxyl value of the polyester polyol (A) is 10
0 to 250. The scratch-resistant coating composition according to claim 1. (3) The etheric oxygen content in the polyester polyol (A) is 0.2 to 2.0%, Claim 1
The scratch-resistant coating composition described in .