JPS60260615A - Production of polyurethane resin - Google Patents

Abstract

PURPOSE:To produce the titled low-toxicity, irritating odor-free resin capable of forming a high-solid coating and a paint film of excellent appearance, by reacting a polyol with a specified triisocyanate compound. CONSTITUTION:A polyurethane resin is produced by reacting a polyol (e.g., trimethylolpropane, glycerin, or polypropylene glycol) with 1,6,11-undecane triisocyanate. This resin has properties inherent in a polyurethane resin, such as excellent adhesion to substrates, excellent balance between hardness and flexibility, cracking resistance, water resistance, chemical resistance, gloss, etc. In addition, the triisocyanate compound used has a low vapor pressure and emits no highly toxic volatile component. This composition can form a film excellent in appearance, heat resistance, and water resistance and form a high-solid coating because of its low viscosity, so that it can be designed as a nonpolluting coating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing polyurethane resins useful for producing polyurethane products such as films, coatings, curing agents, and adhesives, and particularly for producing polyurethane resin paints. It is.

[Prior art]

Polyurethane resin is a general term for polymers containing urethane bonds (-000NH-) in the resin molecules, and the urethane bonds are generated from the reaction between hydroxyl groups (-OH) and isocyanate groups (-NGO). , polymerized. Various polyols or compounds containing active hydrogen are used as the hydroxyl group-containing component, while various isocyanate compounds are used as the isocyanate component. By combining these polyols and isocyanate compounds, polyurethane products with a wide range of performance can be obtained and are used in a wide variety of applications.

Polyurethane resins are classified into yellowing types and non-yellowing types depending on the type of isocyanate compound, and have been applied to each type of use. For example, the yellowing type was developed with a focus on urethane foam, and the market was further expanded to paints, lastomers, and synthetic leather. -The non-yellowing type is mainly used in paints, and has steadily gained a foothold in adhesives, sealants, and related fields.

Most non-yellowing isocyanates are aliphatic compounds, such as hexamethylene diisocyanate, isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, lysine diisocyanate, or derivatives thereof. It is used. In addition, xylylene diisocyanate is also commonly used as a non-yellowing type.

The isocyanate compound used in the present invention belongs to a non-yellowing type, which is one of the major features of the present invention.

These non-yellowing isocyanate compounds exhibit their properties in the field of polyurethane paints, and are used in automobiles, railway vehicles,
] It is used in a variety of fields, including vehicles such as containers, aircraft, seamless floors, coil coatings, ships, woodworking, building materials such as plywood and aluminum sash, and plastics.

Scientifically speaking, isocyanate compounds are highly reactive chemical substances, so it is extremely dangerous for people with allergies or weak respiratory systems to use them. For example, the ultimate atmospheric concentration of monomers such as toluene diisocyanate and diphenylmethane diisocyanate was determined by a committee of the United States Government-affiliated Council of Industrial Hygienists to be 0.02 pl)m. For these reasons, the above-mentioned incyanate monomer is rarely used as it is in polyurethane paints, except in special cases.
It is usually used by modifying it into a prepolymer (adduct) added to trilomethylolpropane, ethylene glycol, etc. This modification has the effect of lowering the vapor pressure, thereby reducing toxicity and odor, as well as adjusting reactivity and making coatings more versatile.

[Problem that the invention seeks to solve]

Although these prepolymer adducts have extremely low vapor pressure at room temperature, it is extremely difficult industrially to completely remove the isocyanate monomer from the prepolymer adducts.
The monomer concentration in commercially available polyisocyanates is usually 0.7%.
Contained within the following range. However, on the other hand, highly toxic diisocyanates are present in commercially available incyanate prepolymers, albeit in small amounts, which can cause a strong irritating odor during paint formulation and painting operations.
...Many people complain of respiratory disease symptoms specific to cyanate, and this problem has come into focus as the use of polyurethane products increases.

In particular, isocyanate adducts are said to liberate diisocyanates, so-called highly toxic diisocyanate, depending on the storage conditions during storage, which is a cause for concern for engineers and workers.

Under these circumstances, work environments are being improved by providing sufficient ventilation to prevent workers from directly inhaling isocyanate compounds, but the current situation is that this is still not sufficient.

In view of these circumstances, the present inventors have made earnest efforts to develop a polyurethane resin using a trifunctional isocyanate compound that does not contain any highly toxic volatile monomers and has no irritating odor, and have thus arrived at the present invention. be.

[Means for solving problems]

In order to achieve the above object, the present invention consists of the following configuration.

"A method for producing a polyurethane resin characterized by reacting a polyol with 1.6.11-undecane triisocyanate." 5. The trifunctional isocyanate compound used in the present invention is the following (I
) It is a new compound having a chemical structure represented by the formula.

0CN-(CH2>5-CH-(CH2>5-NG
O(I)NGO This compound has a linear hydrocarbon chain as its molecular skeleton, with primary carbon atoms at both ends and 6 atoms in the center of the molecular skeleton.
Isocyanate group (-NGO
is a highly symmetrical compound with three isocyanate groups in the molecule, and its boiling point is 166-167°C, 10.2 mm HO, and it is a colorless compound with excellent fluidity at around room temperature. It is an odorless liquid substance.

This compound has an extremely advantageous property that it has an extremely low vapor pressure near room temperature, is not irritating to the human body, and can be handled safely.

Further, this triisocyanate has a high isocyanate content of 45% or more.

This value is a high value that cannot be obtained with conventionally known polyisocyanates which are odorless and have a 6-low vapor pressure at room temperature. Furthermore, this compound has an extremely low viscosity at room temperature, so there is no need to lower the viscosity with a diluent as with existing products, so it can be used practically as a triisocyanate with a high isocyanate content. .

In general, this triisocyanate does not contain unsaturated bonds or beta atoms such as oxygen atoms or nitrogen atoms in its molecular skeleton, so this compound itself is not only stable against heat and light, but also isocyanate Their use in fields where photostability is required for products made from the compounds has particularly beneficial results. Furthermore, this compound has an extremely symmetrical molecular structure and can impart excellent properties to products derived from this compound.

The compound represented by the above formula (I) has already been provided as prior art by the present applicant (Japanese Patent Application No. 53-73
196@, Japanese Unexamined Patent Publication No. 55-327).

Further, one typical example of the polyurethane resin of the present invention has the following structural unit.

IU (However, R1, R2, and R3 each represent the same or different polyol residues.) On the other hand, the term "polyol" as used in the present invention refers to a compound or polymer containing two or more hydroxyl groups per molecule. It is inclusive. Examples include diols, triols, tetraols, pentols, hexitols, and mixtures thereof, as well as polyesters, polyethers, polyester polyols, and polymer polyols containing two or more hydroxyl groups per molecule; You can also use Specifically, the following compounds are listed: 1. (I can do that.

Diol ethylene glycol, propylene glycol, β, β′
-dihydroxy diethyl ether (diethylene glycol), dipropylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, polyethylene glycol, polypropylene glycol, polypropylene-polyethylene glycol, polybutylene glycol polyol glycerin, trimethylolpropane, pentaerythritol, Sorbitol, 2-methylglucoside, 1,
2. Compounds having two or more hydroxyl groups in one molecule such as 6-hexandriol Polyether polyols Prepared by adding propylene oxide, ethylene oxide, etc. to a polyhydric alcohol such as glycerin or propylene glycol.

Also included are polyether polyols rich in hydroxyl groups, which are obtained by reacting ethylene oxide or propylene oxide with a polyfunctional compound such as ethylenediamine or ethanolamine.

Polyester polyol It is synthesized by the condensation reaction of carboxylic acids such as adipic acid, dimer acid, phthalic anhydride, and isophthalic acid with diols and triols such as ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, and glycerin.

A polymerizable monomer having one or more hydroxyl groups in one molecule of a polymer polyol;
It can be prepared by copolymerizing this with other copolymerizable monomers.

A polymerizable monomer having one or more hydroxyl groups in one molecule is represented by the following general formula.

10- (In this formula, n=1.2 m=1.2.3 R: Alkylene group having 2 to 12 carbon atoms, which may be substituted with other atoms such as halogen.) For example, acrylic acid-2- Hydroxyethyl, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methacrylic acid
3-hydroxypropyl, 4-hydroxybutyl methacrylate, methacrylic In-2-e droxypentyl,
Furthermore, methacrylic acid monoester of glycerin, methacrylic acid monoester, or acrylic acid-2-
Hydroxy-3-chloropropyl and the like.

Examples of other monomers that can be copolymerized with the above-mentioned hydroxyl group-containing acrylic esters and methacrylic esters are as follows.

(1) Acrylic acid or its ester, e.g. 1
1-methyl acrylate, ethyl, propyl, butyl, decyl, 2-ethylhexyl, lauryl, etc.

(2) Methacrylic acid or its esters, such as methyl methacrylate, ethyl, butyl, decyl, 2-ethylhexyl, lauryl, etc.

(3) Styrene or its derivatives, such as α-methylstyrene and β-chlorostyrene.

(4) Vinyl esters, such as vinyl acetate, vinyl propionate, vinyl isopropionate, etc.

(5) Nitriles, such as acrylonitrile and methacrylonitrile.

In addition, acrylic acid, methacrylic acid, Cardura E (
Monoepoxy compounds such as Shell Chemical Co., Ltd.) or polymerizable adducts produced by addition reactions with epoxy resins such as Epicote 1001 (Shell Chemical Co., Ltd.) may also be used. , 1 (, Among the various monomers mentioned above, the most preferred one is hydroxyalkyl (meth)
For acrylate 12-, methacrylic acid-2-hydroxyethyl, acrylic acid, -2-hydroxyethyl, methacrylic acid-2-
Hydroxypropyl, and other monomers include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, lauryl methacrylate, acrylic acid, methacrylic acid, styrene, acrylamide, vinyl acetate, etc. It will be done.

Further, in order to prepare a suitable polymer polyol, it is preferable to select the amount of each monomer to be used as follows.

A, hydroxyalkyl (meth)acrylate 5-30
Weight% B, 50-90% by weight of acrylic acid alkyl ester or (and) methacrylic acid alkyl ester C0 Other ingredients as required O-50% by weight D, 0-10% by weight of acrylic acid or methacrylic acid In the above, hydroxy If the amount of alkyl (meth)acrylate 13-lylate is less than 5% by weight, the degree of crosslinking due to reaction with the isocyanate compound will be too small, making it impossible to obtain a coating having the expected performance.

A polymer polyol obtained by copolymerizing the monomers described above can be produced by known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, and suspension polymerization, but solution polymerization is usually carried out.

Although various polyols have been specifically exemplified above, the polyol of the present invention is not limited to these,
Any polyol that can react with the trifunctional isocyanate compound used in the present invention to form a urethane bond can be used, and various combinations can also be selected.

The preferred hydroxyl value for the above various polyols is 20 to 1.
ooo, particularly preferably in the range of 20 to 500. Moreover, the range of 50 to 1000 is particularly excellent for high solid type compositions. When the hydroxyl value is 20 or less, the degree of crosslinking due to the reaction with the isocyanate compound is reduced, resulting in a non-yellowing type.14- Various performances required for polyurethane applications, especially solvent resistance,
Water resistance and weather resistance become unsatisfactory. On the other hand, the hydroxyl value is 1
On the other hand, if it is more than 000, the degree of crosslinking becomes excessive and the mechanical properties of the crosslinked film are significantly reduced, making it brittle and having poor impact resistance, which is not preferable.

The polyurethane resin of the present invention is synthesized from the various polyols described above and the trifunctional isocyanate compound described above, and is used to manufacture various polyurethane products including films, coatings, elastomers, foams, curing agents, adhesives, etc. It can be used for.

By adjusting the type of polyol and the ratio of NC010H in the composition, various performance and physical properties such as film strength, flexibility, chemical resistance, and solvent resistance can be changed over a wide range, depending on the purpose. Can be used for any purpose.

The NGO10H ratio (molar ratio) in the composition of the present invention is 0.5
Compositions in the range ˜2.0 are suitable for the production of films and coatings. For polyurethane 15- paints, an NGO10H ratio of 0.5 to 1.2 is particularly suitable. Those with an NGO10H ratio of 0.5 to 1°O are useful in the electrical insulation field, encapsulation field, and cast products.

Furthermore, when the NGO10H ratio is 0.1 to 0.7, it is preferable for producing advanced adhesives or hardeners;
If the 10H ratio is large, it is suitable for foam production. Foaming can be carried out by introducing an amount of water or a blowing agent into the reactant by known foaming techniques.

The polyurethane resin paint obtained by the present invention can be applied to commonly used two-pack type or one-pack type, and can be used for a wide range of applications. Examples of types of paint and their uses are as follows.

(1) Two-component polyol A urethane bond is generated by the addition reaction between the curable isocyanate group and the hydroxyl group of the polyol, forming a coating film. Examples of polyol components include polyester polyols made of polybasic acids and bitroxyl compounds, polyether polyols made of diol- or triol-type pro-16-pyrene oxide polymers, and acrylic polyols made of copolymers of acrylic monomers having hydroxyl groups. Are better. Depending on the type of polyol and the combination with the isocyanate compound, it can be made from flexible to hard and strong, and has excellent weather resistance, water resistance, chemical resistance, and stain resistance. It is usually used at a temperature ranging from room temperature to 120°C. This type is metal,
It has excellent adhesion to non-coated materials such as nonferrous metals, plastics, rubber, leather, and concrete, and is used in a wide range of applications such as building materials, automobiles, machinery, equipment, aircraft, railway vehicles, ships, and woodwork. Ru.

(2)-Liquid type heat-curing type Since the reaction of the above-mentioned positive wave polyol-curing type proceeds even at room temperature, the pot life of the paint is often a problem.

For this reason, the isocyanate group of the isocyanate compound is blocked with a blocking agent, and although stable at room temperature, the blocking agent is dissociated by heating to regenerate the isocyanate group, and a coating film is formed by the reaction between the hydroxyl group and 17-. Heat-curing methods have also become common. This method is suitable for applications that require storage stability at room temperature, such as automobile line painting.

As polyols to be combined with block type isocyanate prepolymers, polyester polyols and acrylic polyols are mainly preferred.

As the blocking agent for masking the free isocyanate groups of the trifunctional isocyanate compound used in the present invention, commonly used blocking agents can be used, including the following.

Phenol, m-nitrophenol, p-chlorophenol, catechol, ethyl malonate, acetylacetone, ethyl acetoacetate, Talezol, ε-caprolactam, methyl ethyl ketoxime, cyclohexanone oxime, butyl mercaptan, methanol, ethanol, ethylene chlorohydrin Such.

The dissociation temperature of the above-mentioned blocking agent varies depending on its type, but generally requires heating to at least 120'C. Because this mold requires baking at a relatively high temperature, it is mainly used in fields such as electric wires, but new developments are expected such as application to powder paints based on polyurethane resin and water-based emulsion paints. be done.

By the way, it goes without saying that the solvent used for polyurethane resin paint must not have active hydrogen atoms.
The same applies to the composition of the present invention. Therefore, even if the polyol is dissolved, it cannot be used that reacts with the isocyanate group. For example, those with basic nitrogen atoms such as alcohols, dimethylformamide, and pyridine should be avoided. Examples of solvents that can be used in the present invention include the following.

Hydrocarbon solvents bempine, toluene, xylene, aromatic naphtha ester solvents ethyl acetate, butyl acetate, cellosolve, hexyl acetate,
Amyl acetate, ethyl propionate, 19-butyl propionate ketone solvents Acetone, methyl ethyl ketene, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone glycol ester solvents ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate The above solvents When a hydrocarbon solvent, which is a non-polar solvent, is used as a solvent for a polyol component or an isocyanate compound, it may result in a non-uniform or opaque solution, and its use alone may be inappropriate. In addition, esters are the most commonly used in terms of their solubility, but care must be taken as impurities such as alcohol, acid, and water are likely to be mixed in.

The coating composition according to the present invention can be applied by spray coating.5. I
Q: It can be applied to the object by the usual methods such as package coating, dip coating, and roller coating. In addition, plasticizers or small amounts of additives added during coating or painting can also be used within their customary amounts. Similar to solvents, when selecting pigments, it is necessary to pay attention to moisture content in addition to various properties, and extender pigments in particular have a high moisture adsorption capacity.

Catalysts can also be used to accelerate drying and curing.

For example, tertiary amines such as dimethylethanolamine and triethylenediamine, and salts such as stannath octoate and dibutyltin dilaurate can be used.

The reaction temperature for producing polyurethane products is from 20 to
A range of 160°C is preferred. The preferred reaction is between isocyanate groups and hydroxyl groups to form urethane bonds. However, reactions between isocyanate groups and active hydrogen atoms other than hydroxyl groups can also be carried out. Examples of such active hydrogen donors include amines, acids, substituted ureas, urethanes,
Examples include amines. Specifically, the isocyanate group reacts roughly at a relatively high temperature with the -NH group of the urethane bond formed by the reaction with the hydroxyl group to form an allophanate bond.

Similarly, a biuret bond is formed from a urea bond and an isocyanate group, and an acylurea bond is formed from an amide bond and an isocyanate group. A wide range of different reactions are possible in this way and these can be utilized depending on the intended application.

If necessary, reinforcing agents commonly used in the art, such as antioxidants, pigments, plasticizers, catalysts, surfactants, etc., can also be added to the reactants.

〔Example〕

Next, the present invention will be specifically explained with reference to Examples.

Examples 1-7 The ingredients shown in Table 1 are mixed to obtain a homogeneous material. This liquid was cast onto a tin plate, cured at 100°C for 4 hours, and then cured at 120°C for 2 hours. Films with various properties were obtained, and all had good gloss.

22- Table 1 1231 Example 8 A polyester polyol is prepared as follows.

Neopentyl glycol 126.9 parts Trimethylolpropane 22.1 parts Adipic acid 72.3 parts Isophthalic acid 123.2 parts This mixture was placed in a reaction vessel and heated and stirred at 200'C for 30 minutes. Next, bubble viscosity F (solid content in methyl ethyl ketone 60%), acid value 10. Heating and stirring were continued at a temperature of 220'C with water flowing out until the hydroxyl concentration reached 100 (about 15 hours). Methyl ethyl ketone was added to the reactant while cooling it to adjust the solid content to 60%, thereby preparing a polyester polyol solution.

Next, 1,6,11-undecane triisocyanate obtained by the method described in Japanese Patent Application No. 73196/1986 is added to this polyol solution so that the hydroxyl groups and isocyanate groups are equal in amount, and mixed uniformly.5. (() The film produced by coating and curing this mixture had excellent gloss and very good mechanical properties.

〔Effect of the invention〕

The polyurethane resin of the present invention is particularly useful for polyurethane resin coatings. Polyurethane paints generally have excellent adhesion to various objects, balance between hardness and flexibility, crack resistance, water resistance, chemical resistance, gloss, etc., and the polyurethane resin paint obtained by the present invention also has excellent properties. In addition to having excellent performance, it also has superior features compared to commercially available polyurethane resin paints, which will be described later. All of these features depend on the trifunctional isocyanate compound used in the present invention, and are features not found in commercially available non-yellowing polyisocyanates (prepolymers or adducts).

When comparing the performance of polyurethane resin paints using commercially available non-yellowing polyisocyanates and the same polyol (NGO10H ratio constant), the features of the paints according to the present invention are as follows.

(1) Low-toxicity hexamethylene diisocyanate-based prepolymers or adducts generally have a fairly strong pungent odor. This is said to be due to the presence of a trace amount of hexamethylene diisocyanate monomer in the prepolymer or adduct. -6 The trifunctional isocyanate compound used in the present invention has an extremely low vapor pressure and does not release highly toxic volatile components during storage. Also, the NCO content is higher than commercially available products. Therefore, there is almost no irritating odor peculiar to isocyanates in paints, and the amount of isocyanate components relative to the amount of polyol components can be reduced in view of the high NCO content, which is extremely advantageous for health.

(2) The appearance of the paint film is easily improved.

The gloss and texture of a paint film are related to various factors, but the influence on the base cannot be overlooked. In the composition of the present invention, various solvents, especially aromatic solvents, can be used extensively, so that the influence on the substrate (for example, primer surfer) is small, and the appearance of the coating film is easily improved because the solvent does not penetrate much. Suitable for applications where appearance is important, such as automotive paint.

(3) Excellent acid resistance and water resistance in coating film performance 2
6- Ru. This is not only due to the above-mentioned high curing speed, but also largely related to the network structure cured with the trifunctional isocyanate compound used in the present invention.

(4) Can contribute to high solids.

In recent trends, high solids or solvent-free polyurethane resin paints are attracting attention as a pollution control measure. Like the polyol component, the isocyanate component used in this paint is required to have a low viscosity at room temperature. Since the trifunctional isocyanate compound used in the present invention has a low molecular weight, it has a low viscosity and can be used as a paint for pollution control. Depending on the selection of polyol, it is also possible to make it solvent-free, which can also contribute to resource and energy savings.

Patent Applicant Higashi Stock Exchange Company 27-

Claims (1)

[Claims] (1) A method for producing a polyurethane resin, which comprises reacting a polyol with 1.6.11-undecane triisocyanate.