JPS592685B2 - Urethane prepolymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to urethane prepolymer compositions having terminal isocyanate groups.

More specifically, 3-isocyanatomethyl-3, 5,
The main component is an adduct of 3 moles of 5-trimethylcyclohexyl isocyanate (also called isoborone diisocyanate, hereinafter abbreviated as IPDI) and 1 mole of trimethylolpropane, and has very good solubility in organic solvents and polyol components for coatings. The present invention relates to isocyanate-terminated urethane prepolymer compositions that provide coatings with highly improved weather resistance. Various urethane paints are currently on the market, but they generally have poor weather resistance and are susceptible to yellowing when exposed to light. Especially tolylene diisocyanate (TDI)
) type paints have extremely poor weather resistance. Hexamethylene diisocyanate (HDI) is used to improve weather resistance.
), aliphatic paints such as 4,4'-synchrohexylmethane diisocyanate, and xylylene diisocyanate (XDI) paints have been devised, but satisfactory results have not yet been obtained. In view of these circumstances, the present inventors have conducted various studies to improve the weather resistance of urethane paints, and have found that, in general, coating films obtained from adducts of IPDI and low-molecular-weight polyols have excellent weather resistance. However, further research on the low molecular weight polyol components to be reacted with this IPDI revealed that ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1 When glycols such as , 6-hexanediol, and neopentyl glycol are used, the drying properties of paints obtained by combining these adducts with acrylic polyols are poor, and the hardness of the paint film is low, making it difficult to use as a practical paint. I found out that there is no sex.

Also, glycerin, 1,2,6-hexanetriol,
When using triols such as trimethylolethane or polyols with more than four functional functions such as pentaerythritol, sorbitol, and sucrose, when combined with acrylic polyol to form a paint, the paint film has poor adhesion and impact resistance. It was discovered that it has no practical use as a paint. However, it has been found that a coating film of an adduct obtained using trimethylolpropane as a low-molecular polyol component has relatively good adhesion and impact resistance. Based on this knowledge, the present inventors conducted further research and found that
When producing an adduct of IPDI and trimethylolpropane, a method commonly used in the polyurethane field is to convert IPDI and trimethylolpropane into NCO
It was found that the adduct obtained by reacting at a /0H ratio of 2.0 (3 moles of IPDl and 1 mole of trimethylolpropane) has poor compatibility with acrylic polyols and the like. In this case, in addition to an adduct of 3 moles of 1PDI and 1 mole of trimethylolpropane (hereinafter abbreviated as 3:1 adduct), for example, an adduct of 5 moles of IPDI and 2 moles of trimethylolpropane (hereinafter referred to as 5:2 adduct) It is presumed that a large amount of adducts (hereinafter referred to as adducts) or adducts with higher molecular weights are produced as by-products, and these by-products and IPDI monomers adversely affect the compatibility with the acrylic polyol. However, it contains 65% by weight or more of the 3:1 adduct and
A urethane prepolymer composition containing 5% by weight or less of PDI monomer not only provides a coating film with excellent weather resistance, but also provides coating polyols (polyester polyol, polyether polyol, polyester ether polyol, It has been found that it has very good compatibility with oil-modified polyester polyols and acrylic polyols and also has very good solubility in organic solvents, and can be particularly advantageously used as a prepolymer for urethane paints. The present invention is based on the above findings and further research,
This was completed after repeated consideration.

In the composition of the present invention, the 3:1 adduct is represented by the following formula. In the above formula, -1PDI means 0 of the two NCO groups of PD, one of which is trimethylolpropane.
Indicates one that reacts with H group and the remaining one is a free NCO group.

The composition of the heather invention includes (1) 65% by weight of the above 3:1 adduct;
or more, preferably 70% by weight or more, more preferably 75% by weight or more
(2) IPD monomer in an amount of 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less.

Components other than the above include, for example, 5:2 adduct, 5:
One that has a higher molecular weight than the 2-adduct is considered. The content of the 3:1 adduct and IPD monomer in the urethane prepolymer composition can be determined by analytical methods such as gel permeation chromatography (GPC). The composition of the heather invention may be manufactured by any method.

That is, after reacting IPDl and trimethylolpropane in an arbitrary ratio, by-products other than the 3:1 adduct and IPDI monomer in the reaction solution are removed by appropriate means. It will be done. The reaction between IPD and trimethylolpropane can be carried out without a solvent.
Furthermore, the reaction can also be carried out in a solvent having no active hydrogen (eg, ethyl acetate, butyl acetate, tetrahydrofuran, dimethylformamide, dimethylacetamide, methyl ethyl ketone, dioxane, etc.). In order to minimize the amount of by-products, it is conceivable to increase the equivalent ratio of IPDI to trimethylolpropane (NCO/OH). During the reaction between IPDI and trimethylolpropane, it is preferable to add an organometallic catalyst such as those commonly used in the polyurethane field. Examples of the catalyst include distanoxanes such as tetrabutyl-1,3-diacetoxydistanoxane, dibutyltin cyclolade, dibutyltin oxide, dibutyltin dilaurate, stannous octylate, lead benzoate, lead naphthenate, and iron acetyl. acetonate, cobalt benzoate,
Examples include zinc 2-ethylhexanoate and zinc naphthenate, with organotin catalysts being particularly preferred. The amount of catalyst used is about 0.01 to 5% by weight, especially about 0.03% by weight based on PD.
~2% by weight. By-products and IPD from the reaction solution
Examples of means for removing the I monomer include an extraction method, a distillation method, a chromatography method, a precipitation method, or a combination thereof.

In the case of the extraction method, the difference in solubility in the extractant between the 3:1 adduct and IPDI monomer is used. The equivalent ratio with methylolpropane is 3~
8, particularly preferably in the range of 4 to 6.

Aliphatic hydrocarbons are used as extractants. Among such aliphatic hydrocarbons, those having a boiling point of 50. ~100°C is preferable, specifically, for example, n-heptane,
n-hexane, ligroin, n-octane, 3-methylpentane, 3-ethylpentane, petroleum benzine, or mixtures thereof are used. Since both the generated 3:1 adduct and unreacted 1PDI have good solubility in organic solvents, it is possible to remove only unreacted IPDI with an extractant and obtain the desired prepolymer with high purity in a good yield. This is extremely difficult and for this purpose it is preferable to carefully select the type of extractant.

From this point of view, among the above extractants,
N-hexane is preferred. The extraction temperature is 15-90°C, preferably 30-60°C. The extraction operation is carried out in a conventional manner and may be continuous or batchwise, and the amount of extractant used in the continuous method is 1 to 4 times the weight of the reaction product, preferably 2 to 3 times the amount in the batch method. In this case, the amount used is 2 to 6 times, preferably 3 to 5 times. The unreacted IPDI extracted into the extractant is reused for reaction with trimethylolpropane after the extractant is removed by an operation such as distillation. When using the distillation method, it is preferable to make the equivalent ratio of IPDI and trimethylolpropane as large as possible in order to reduce the amount of by-products in the reaction solution, but considering economic efficiency, the ratio is preferably 3 to 10. is 4-7.

Distillation can usually be carried out in batches, but in order to prevent deterioration due to heating during distillation, it is preferable to use continuous thin film distillation, which requires a relatively short residence time. Specifically, for example, the reaction solution may be heated at about 150 to 20% under a vacuum of 1.0 to
When heated to 0°C and subjected to continuous thin film distillation, IPD
Monomer can be distilled off to less than 5%. The removed unreacted 1PDI is reused for the reaction. Examples of the chromatographic method include column chromatography, thin layer chromatography, and paper chromatography.

Although any equivalent ratio between IPDI and trimethylolpropane may be used, it is particularly preferable that the ratio is from 3 to 10. The operation method is usually carried out in accordance with the separation and purification of compounds in the field of chemistry. Since the urethane prepolymer composition of the present invention has a free NCO group at the end, it is preferable to carry out the treatment under a nitrogen atmosphere as quickly as possible. The precipitation method is usually carried out according to the method used in the field of polymer chemistry.

For example, after dropping the reaction solution of IPDI and trimethylolpropane into a poor solvent for byproducts such as 5:2 adducts to precipitate and remove byproducts such as 5:2 adducts, this supernatant A high proportion of the 3:1 adduct is obtained by further adding a poor solvent to the solution and precipitating the 3:1 adduct. The equivalent ratio of IPDI to trimethylolpropane is preferably about 1.3 to 2.0. Examples of the poor solvent include the solvents used in the above extraction method. The urethane prepolymer composition thus obtained has an amine equivalent weight of approximately 240 to 350, and has excellent solubility in organic solvents.

For example, it is soluble in ethyl acetate, butyl acetate, cellosolve acetate, benzene, toluene, xylene, methyl ethyl ketone, etc. The composition of the present invention is generally diluted with a solvent and used as an isocyanate component in two-component urethane paints, but it is usually diluted with ethyl acetate to have a solid content of 20 to 20%.
It is used as a 75% by weight solution and mixed with a polyol component for urethane paints.

Further, the urethane prepolymer composition of the present invention can be used, for example, with polyester polyol, polyether polyol,
It has excellent compatibility with a wide range of polyols used as polyol components for urethane paints, such as polyester ether polyols, oil-modified polyester polyols, and acrylic polyols, and is uniformly compatible with these polyols to produce transparent varnishes.

Therefore, the coating film obtained from this varnish or enamel containing pigments has excellent gloss, and the weather resistance, adhesion and impact resistance of the coating film are extremely good. Next, examples and comparative examples will be given as specific examples of the present invention.

In Examples and Comparative Examples, parts indicate parts by weight, and % indicates weight %. Example 1 200 parts of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI),
Add 1 or 2 parts of dibutyltin dilaurate and heat to 80°C.

Trimethylolpropane (TMP) molten in this 17
．． 9 parts were added dropwise over 1 hour while stirring. NCO at this time/
0H is 4.5. After the dropwise addition is completed, heating and stirring at 75 to 80°C is continued for 3 hours. The amine equivalent weight of the reaction mixture at this point is 155.8 (theoretical value 155.6). The reaction solution was subjected to continuous thin film distillation at about 170 to 175° C. under a reduced pressure of 1 Hg to remove the IPDI monomer. The content of 3:1 adduct and free IP contained in the residue were determined by gel permeation chromatography (GPC).
The DI was measured to be 76% and 2.00, respectively!
). Ethyl acetate is added to this residue so that the solid content becomes 75%, and the mixture is uniformly dissolved. The amine equivalent weight of this prepolymer solution is 380. This prepolymer solution has extremely good solubility in organic solvents and can be diluted infinitely with ethyl acetate, butyl acetate, benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, etc.

In order to compare the solubility of the urethane prepolymer solution obtained here with other prepolymers for urethane paints,
A solvent was added to each of the following resins (solid content: 75%), and the volume (dilution) until it became cloudy was measured.

The results are shown in Table-1. However, as a prepolymer for other urethane paints, 3-isocyanatomethyl 3,5,5
- Equimolar hexamethylene diisocyanate and ω, ω2 instead of trimethylcyclohexyl isocyanate
-diisocyanate-1,3-dimethylbenzene, respectively, and are referred to as HDI system and XDl system in Table 11, respectively. Note that the prepolymer obtained by the method of the present invention was expressed as IPDI-based. In order to compare the compatibility of the urethane prepolymer obtained here with polyol components or with known additives with other prepolymers for urethane paints, one part of the resin (both solids content 75%) was used.
Lastrazol-A-80, an acrylic polyol
1 (manufactured by Dainippon Ink Co., Ltd., solid content 50%, 0H value 50) 3
part or cellulose acetate butyrate (EAB5
5l-0.2 manufactured by Eastman Kodatsu, solid content 200
3 parts of the methyl isobutyl ketone solution of 1) was added, stirred well, and its appearance was examined.

The results were as shown in Table-2. In Table 2, the meanings of the symbols for prepolymer 1 are the same as in Table 1. Compatibility with polyols and additives are both 1PDI
It can be seen that the system is excellent. A coating film (PWC4O%) was prepared by combining the prepolymer solution of the heather example with a polyester polyol (Desmohen 1100) containing rutile titanium oxide.

In particular, here, a product obtained by carrying out the same operation as in the present invention using H6XDl (1,3-bisisocyanatomethylcyclohexane) was given as a comparative example as a H6XDl system. The weather resistance of the paint film was examined by irradiating it with ultraviolet rays and the results compared with other paint films are shown in Table 3 in NB.S units.
Shown below. The PDI system, HDl system, and XD system in Table 3 are the same as those in Table 1. As shown in Table 3, IPDI-based coatings are stable against ultraviolet rays and are particularly resistant to yellowing.

This is clearly recognized from the values of ΔB and ΔE. When comparing the coating film of the present invention with that of the H6XDI system, a difference of 1.19 in the Δb value and 0.95 in the value of ΔE was observed, and the coating film of the present invention was found to be different from that of the H6XDI system. It can be seen that it is clearly superior when compared with Example 2 1 part of tetrabutyl-1,3-diacetoxydistanoxane is added to 200 parts of IPD and heated to 70°C.

26.8 parts of molten trimethylolpropane was added dropwise to this mixture over 1 hour while stirring. In this case, NCO/0H is 3.
It is 0. After completion of the dropwise addition, heating and stirring at 70 to 75°C is continued for 3 hours. The amine equivalent at this point is 188,8 (
The theoretical value is 189.0). Example 1. In the same manner as above, unreacted 1PDI was removed to obtain a residue.

The 3:1 adduct and free IPD contained in the residue were 68 (fl) and 2.0%, respectively. Ethyl acetate was added to the residue so that the solid content was 75%, and the mixture was uniformly dissolved to obtain a clear prepolymer solution having an amine equivalent of 389. Example 3 1.5 parts of stannous octylate is added to 200 parts of 1PDI and heated to 80°C.

3.4 parts of molten TMPl was added dropwise to this solution over 1 hour while stirring. NCO/0H in this case is 6.0. After the dropwise addition is completed, stirring is continued at 75 to 80°C for 3 hours. The amine equivalent weight at this point is 142.5 (theoretical value 142.3). Example 1. Unreacted PD was removed in the same manner as 53.
．． 4 parts of residue were obtained (yield 25% based on total charge).

3:1 adduct and free IPDI contained in the residue
were 79% and 2%, respectively. 75% solids
Ethyl acetate was added to the residue to uniformly dissolve it to obtain a clear prepolymer solution having an amine equivalent of 385. Comparative Example 1 1 PD2OO part is heated to 80°C, and 7.9 parts of TMPl is added dropwise over 1 hour with stirring.

NCO/0H at this time was 4.5, the same as in Example 1.

After the dropwise addition was completed, heating and stirring at 75 to 80°C was continued for 5 hours. The amine equivalent at this point was 155.7 (theoretical value 15
5,6). Example 1. The unreacted 1PD1 monomer was removed by thin film distillation in the same manner as above. The content of 3:1 adduct and IPDl was determined to be 54% and 2.2%, respectively.

Example 1. In the same manner as above, an ethyl acetate solution of prepolymer 1 with a solid content of 75 (Ff) was obtained.

Comparative Example 2 1.2 parts of dibutyltin dilaurate is added to 200 parts of IPDI and heated to 80°C.

17.9 parts of molten trimethylolpropane was added dropwise to this mixture over 1 hour while stirring. The NCO/0H at this time is the same as that of Example 1. It is the same as 4 and 5. After finishing dropping, add another 75~8
Continue heating and stirring at 0°C for 3 hours. The reaction mixture contained 35% each of the 3:1 adduct and free PDI.
and 54%. Add 72% of ethyl acetate to this reaction mixture.
．． 6 parts were added and mixed uniformly to obtain a clear prepolymer solution having an amine equivalent of 207.7. Comparative example 3IPD200
1.2 parts of dibutyltin dilaurate was added to the mixture and heated to 80°C.

TMP4O melted in this. 2 parts are added dropwise over 1 hour while stirring. NCO/0H at this time is 2.0. TMP
After the completion of the dropwise addition, heating and stirring at 75 to 80°C is continued for 3 hours. The amine equivalent at this point is 266.6 (theoretical 26
6.9). Hereinafter, unreacted 1P was prepared in the same manner as in Example 1.
DI was removed.

The 3:1 adduct and free PDI contained in the residue were 58% and 1.8%, respectively. Solid content is 75
Ethyl acetate was added to the residue to uniformly dissolve it to give a clear prepolymer solution with an amine equivalent of 397.
Example 4 The urethane prepolymers obtained in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were copolymerized with 45 parts of styrene, 45 parts of methyl methacrylate, and 10 parts of 2-hydroxyethyl methacrylate. acrylic polyol (
The coating film performance when applied in combination with 50% solids content and 0H value 20) was investigated.

Table 4 shows the results. The coating film test was carried out at 45℃ after application.
This was done after leaving it in the sun. Example 5 Zinc naphthenate (14.5% Zn
) Add 1.2 parts and heat to 80°C.

Trimethylolpropane (TMP) molten in this 17
．． 9 parts were added dropwise over 1 hour while stirring. NCO at this time/
The 0H ratio is 4.5.

After completion of the dropwise addition, heating and stirring at 75 to 80° C. is continued for 3 hours. The amine equivalent at this point was 155.9 (theoretical value 1
55.6). After the reaction was completed, unreacted 1PDI monomer was removed by thin film distillation. When the amounts of the 3:1 adduct and IPDI contained in the residue were measured, they were found to be 7.
20! ) and 2.2%. This is Example 1. Similarly, add ethyl acetate so that the solid content is 75%,
Dissolve uniformly. The amine equivalent weight of this prepolymer solution is 383.

Example 6 200 parts of IPDI, lead naphthenate (30.0%Pb)
Add 1 or 2 parts and heat to 80°C.

Trimethylolpropane (TMP) molten in this 17
．． 9 parts were added dropwise over 1 hour while stirring. NCO at this time/
The 0H ratio is 4.5.

After completion of the dropwise addition, heating and stirring at 75 to 80° C. is continued for 3 hours. The amine equivalent at this point was 156.1 (theoretical value 1
55.6). After the reaction was completed, unreacted IPDI was removed in the same manner as in Example 1. When the amounts of 3:1 adduct and 1PD contained in the residue were measured, they were found to be 73.
% and 2.001). As in Example 1, ethyl acetate was added to the mixture so that the solid content was 75%, and the mixture was uniformly dissolved. The amine equivalent of this prepolymer solution is 38
It is 5.

The urethane prepolymers obtained in Examples 5 and 6 were combined with acrylic polyol in the same manner as in Example 4, and a coating test was conducted. The results are shown in Table-5. Example
7 137.8 parts of IPDI, 0 iron acetylacetonate,
Add 091 parts and heat to 80°C.

Trimethylolpropane (TMP) 13 melted in this
．． 9 parts were added dropwise over 1 hour while stirring. NC at this time (}
Q{ratio is 4.0. After the completion of dripping, add another 75 to 80
Continue heating and stirring at ℃ for 2 hours. The amine equivalent weight at this point is 169.6. After the reaction is completed, the reaction product is cooled to a temperature of 40 to 45° C., and unreacted 1PDI is extracted eight times with n-hexane while maintaining this temperature. After removing a small amount of n-hexane remaining in the extraction residue by vacuum distillation, the 3:1 adduct and IPD contained in the residue were removed.
The content of I monomer was measured and found to be 70% and 0.2%, respectively. Add ethyl acetate so that the solid content is 75% and dissolve uniformly. The amine equivalent weight of this prepolymer solution is 390.

When a coating film test was conducted in combination with an acrylic polyol in the same manner as in Example 4, a coating film with excellent adhesion and impact resistance was obtained. Comparative Example 4 1.2 parts of dibutyltin dilaurate is added to 200 parts of IPD and heated to 80°C.

79 parts of molten TMPl was added dropwise to this solution over 1 hour while stirring. NCO/0H at this time is 4.5. After the dropwise addition is completed, heating and stirring at 75 to 80°C is continued for 3 hours. After the reaction is complete, cool until the vorticity reaches 40-45°C, and while maintaining this temperature, remove unreacted 1P from the product with n-hexane.
Extract DI four times. The amount of n-hexane is 120 parts for the first time and 100 parts for the second to fourth times. A small amount of remaining n-hexane was completely distilled off to obtain an extraction residue. The 3:1 adduct and free IPDI contained in the residue were 73% and 7%, respectively. Add ethyl acetate so that the solid content is 75% and dissolve uniformly. This prepolymer was combined with acrylic polyol in the same manner as in Example 4, and a coating test was conducted, and the following results were obtained. Dry to the touch 1 minute curing dry 15 minutes Pencil hardness 2H Adhesion (burlap test) (X/100) Dupont impact test %X5OO×10 (inch, G
, (1) 0K

Claims (1)

[Claims] 1 (1) 65% by weight or more of an adduct of 3 moles of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate and 1 mole of trimethylolpropane, (
2) Contains 5% by weight or less of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, with the remainder being (3) 3-isocyanatomethyl-3,5,5
- A urethane prepolymer composition which is an adduct of 5 moles of trimethylcyclohexyl isocyanate and 2 moles of trimethylolpropane or an adduct with a higher molecular weight.