JP2006193450A - Polyol (meth)acrylate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily handleable polyol (meth)acrylate mixture having a primary skin-irritating index sufficiently reduced on practical uses by a profitable method. <P>SOLUTION: This polyol (meth)acrylate mixture obtained by esterifying a polyol mixture comprising ditrimethylolpropane, 2,2'-methylenebis(oxymethylene)bis(2-ethyl-1,3-propanediol), and trimethylolpropane in a specific ratio. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyol (meth) acrylate mixture derived from an alcohol mixture of a specific composition.

  Trimethylolpropane (hereinafter referred to as TMP) is industrially produced in large quantities by the aldol condensation and cross-kanitz allo reaction between normal butyraldehyde (hereinafter referred to as NBD) and formaldehyde under a basic catalyst. One use is (meth) acrylate. Trimethylolpropane triacrylate (hereinafter referred to as TMPTA), which is an acrylate of TMP, is characterized by excellent compatibility, large crosslink density, relatively low viscosity and high reactivity. Used in inks, coatings, adhesives, casting materials, etc. However, TMPTA has a primary skin irritation index (hereinafter referred to as PII) as large as 4.6, and its use requires special attention.

  One of the (meth) acrylates whose PII is significantly reduced from TMPTA is ditrimethylolpropane tetraacrylate (hereinafter referred to as di-TMPTA). Di-TMPTA is not only excellent in compatibility and reactivity, but also has a low PII of 0.3 and high safety, so various inks, coatings, paints, adhesives, casting materials, etc. as UV and electron beam curable monomers Use is spreading.

  Ditrimethylolpropane (hereinafter referred to as di-TMP), which is a raw material of di-TMPTA, is produced as a by-product in the production of TMP, and is obtained by collecting it. That is, after extracting the reaction product solution of NBD and formaldehyde with a solvent, and obtaining TMP by distillation under high vacuum from the obtained TMP extract (crude TMP), in the residue in the distillation kettle from which TMP was distilled off. Generally contains 1-30% TMP and 20-70% di-TMP. Di-TMP is recovered from the residue by mainly crystallization operation.

  However, in the crystallization operation from the residue of the distillation pot of TMP, it is necessary to go through the steps of crystallization using a solvent, solid-liquid separation and drying, which is not only industrially disadvantageous, Since components other than TMP and di-TMP are also contained in a large amount, the yield and purity of the obtained di-TMP are not necessarily satisfactory.

  An object of the present invention is to provide a method for industrially obtaining a polyol (meth) acrylate mixture such as di-TMPTA having a PII value sufficiently small in practical use and easy to handle in a more advantageous manner.

In the crystallization operation for obtaining di-TMP, the major factors that reduce the yield and purity of di-TMP are mainly generated by residual TMP contained in the distillation residue of crude TMP, and TMP2 molecules and formaldehyde. 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) (hereinafter referred to as bis-TMP). However, as a result of intensive studies to solve the above problems, the present inventors have isolated and purified the mixture by limiting the contents of TMP, di-TMP and bis-TMP within a certain range. Even when di-TMP was not used as a raw material for (meth) acrylation, it was found that a polyol (meth) acrylate having a PII value sufficiently small in practical use and easy to handle was obtained, and the present invention was achieved. That is, the present invention is as follows.
(1) A polyol (meth) acrylate obtained by esterification of a polyol mixture containing ditrimethylolpropane, 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol), and trimethylolpropane blend.
(2) The polyol (meth) acrylate mixture according to the above (1), wherein the composition of the polyol mixture satisfies the following conditions (a) to (c).
(A) The weight ratio of the total content of ditrimethylolpropane and 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) to the content of trimethylolpropane is 0.5 to A range of 20,
(B) The weight ratio of the content of 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) and the content of ditrimethylolpropane is in the range of 0.1-15. ,
(C) The total content of ditrimethylolpropane and 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) is 30 to 95% by weight of the total polyol mixture.
(3) Trimethylolpropane produced by the reaction of normal butyraldehyde with formaldehyde in the presence of a basic catalyst is extracted with a solvent, and the solvent is distilled off from the resulting trimethylolpropane extract, and the resulting crude The polyol (meth) acrylate mixture according to the above (1) or (2), wherein the residue obtained by distilling off trimethylolpropane obtained by purifying trimethylolpropane by distillation is used as the polyol mixture.
(4) The polyol (meth) acrylate mixture according to any one of (1) to (3), wherein the primary skin irritation index is in the range of 0 to 2.0.
(5) The polyol (meth) acrylate mixture according to any one of (1) to (4), wherein the viscosity at 25 ° C. measured by a B-type viscometer is in the range of 1 to 1900 mPa · s.
(6) Hardened | cured material formed by hardening | curing the composition containing the polyol (meth) acrylate mixture in any one of said (1)-(5).
(7) An ink, a paint, an adhesive, or a casting material using a composition containing the polyol (meth) acrylate mixture according to any one of (1) to (5) as a raw material.

  As described above, according to the present invention, the PII value is practically used in an industrially extremely advantageous method using a raw material polyol mixture in which the contents of TMP, di-TMP and bis-TMP are limited to a certain range. A polyol (meth) acrylate mixture which is sufficiently small and easy to handle is obtained.

  The di-TMP, which is a component of the alcohol mixture having a specific composition used in the present invention, is represented by the formula (1), and the bis-TMP is represented by the formula (2).

  As a composition of the polyol mixture subjected to esterification, the weight ratio of the total content of di-TMP and bis-TMP and the content of TMP (total weight of di-TMP and bis-TMP / weight of TMP) is preferably Is in the range of 0.5-20, more preferably in the range of 0.6-15, still more preferably in the range of 1-12. When the weight ratio of the total content of di-TMP and bis-TMP and the content of TMP is less than 0.5, the PII value of the resulting polyol (meth) acrylate mixture becomes an excessive value of 2 or more, Use is not effective because it requires special care. On the other hand, even if the weight ratio of the total content of di-TMP and bis-TMP to the content of TMP exceeds 20, no particular inconvenience occurs in the properties of the resulting polyol (meth) acrylate mixture. In order to obtain a simple mixture, it is usually necessary to purify and concentrate the alcohol mixture by an operation such as crystallization, which makes the operation complicated and is not useful in industrial operation.

  The weight ratio of bis-TMP content to di-TMP content (weight of bis-TMP / weight of di-TMP) is preferably in the range of 0.1 to 15, more preferably in the range of 0.15 to 10. More preferably, it is in the range of 0.2-8. Even if the weight ratio between the bis-TMP content and the di-TMP content is out of this range, there is no particular inconvenience in the properties of the resulting polyol (meth) acrylate mixture, but in order to obtain such a mixture, Usually, either component needs to be purified and concentrated by an operation such as crystallization, which makes the operation complicated and is not useful in industrial operation.

  The total content of di-TMP and bis-TMP is preferably in the range of 30 to 95% by weight of the total polyol mixture, more preferably in the range of 40 to 95% by weight, still more preferably 45 to 95% by weight. It is a range. When the total content of di-TMP and bis-TMP is less than 30% by weight of the total polyol mixture, the polyol (meth) acrylate to be obtained can be obtained if there are many low-boiling fractions such as TMP among other components. The PII value of the mixture becomes an excessive value of 2 or more, and special care is required for its use, which is not effective. Further, among the other components, when the fraction having a boiling point higher than that of bis-TMP is large, the viscosity of the polyol (meth) acrylate mixture as the product increases, and particularly in the case of the polyol acrylate mixture, 2000 mPa · s ( 25 ° C.) or higher, and it is difficult to handle. On the other hand, even if the total content of di-TMP and bis-TMP exceeds 95% by weight of the total polyol mixture, there is no particular disadvantage in the properties of the resulting polyol (meth) acrylate mixture, but such a mixture is obtained. For this purpose, it is usually necessary to purify and concentrate either component by an operation such as crystallization, which makes the operation complicated and is not useful in industrial operation.

  The polyol mixture of the raw material containing TMP, di-TMP and bis-TMP used in the present invention is obtained as follows. Butylaldehyde and formaldehyde are reacted in the presence of a basic catalyst, and TMP is separated from the resulting reaction product. At that time, a TMP extract containing substantially no sodium formate can be obtained by extracting with a solvent after or without concentrating the reaction product. The crude TMP obtained by distilling off the solvent used for extraction from the TMP extract was further purified by distillation under high vacuum, so that the TMP product and the residue in the distillation kettle from which TMP had been distilled off, that is, the present invention. The raw material polyol mixture containing TMP, di-TMP and bis-TMP used is separated. In the present invention, as long as the contents of TMP, di-TMP and bis-TMP are limited within a certain range, this raw material polyol mixture may be used directly, or a specific component such as di-TMP. You may use the remainder after acquiring by crystallization operation.

  In preparing a polyol (meth) acrylate mixture by esterifying a polyol mixture containing TMP, di-TMP and bis-TMP, acrylic acid or methacrylic acid is usually used in a stoichiometric ratio or more. Generally, the molar ratio of acrylic acid or methacrylic acid to alcohol (number of moles of acrylic acid or methacrylic acid / number of moles of alcohol) is 1.0 to 2.0, preferably 1.1 to 1.5, more preferably Is 1.15 to 1.45. The reaction uses a catalyst, and the generated water is discharged out of the system by distillation. Such a catalyst is an acidic catalyst such as sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, etc., but the amount used is 0.1 to 10 mol%, preferably 1 to 5 mol based on acrylic acid or methacrylic acid. %, More preferably 1.5-4 mol%. By such an operation, not only the hydroxyl groups of TMP, di-TMP, and bis-TMP but also the hydroxyl groups of other organic by-products contained in the polyol mixture are esterified to (meth) acrylates.

  In order to discharge water produced by the reaction out of the system by distillation, it is advantageous to use an azeotropic solvent. Such an azeotropic solvent has a boiling point of 50 ° C. to 150 ° C. and can be used as long as it can be easily separated from water, but it can be used as an aliphatic hydrocarbon such as n-hexane or n-heptane, cyclohexane or methylcyclohexane. Suitable alicyclic hydrocarbons and aromatic hydrocarbons such as benzene and toluene are suitable. The amount used is usually in the range of 5 to 70% by weight, preferably 10 to 65% by weight, more preferably 15 to 60% by weight of the reaction mixture. The reaction temperature may be in the range of 50 to 150 ° C., but it is advantageous to carry out the reaction in the range of 75 to 120 ° C., more preferably 77 to 115 ° C. from the viewpoint of shortening the reaction time and preventing polymerization.

  Usually, a polymerization inhibitor has already been added to commercially available acrylic acid or methacrylic acid, but a polymerization inhibitor may be added again during the reaction. Such polymerization inhibitors include hydroquinone, methylhydroquinone, phenothiazine, 2,4-dimethyl-6-tert-butylphenol, 3-hydroxythiol, α-nitroso-β-naphthol, p-benzoquinone, 2,5-dihydroxy -P-quinone, N-nitrosodiphenylamine, copper salt and the like. The amount used is usually in the range of 0.001 to 1% by weight, preferably 0.005 to 0.8% by weight, more preferably 0.01 to 0.5% by weight, based on the reaction mixture.

  The polyol (meth) acrylate mixture of the present invention obtained as described above is separated from the solvent by a method such as atmospheric distillation or reduced pressure distillation, if necessary, by washing with water, brine or an alkaline aqueous solution. It is used for industrial applications.

  The PII value of the polyol (meth) acrylate mixture in the present invention is preferably in the range of 0 to 2.0, more preferably 0 to 1.9, and still more preferably 0 to 1.8. When the PII value exceeds 2.0, there is a high possibility of causing rash on the skin during handling of the PII value, and special caution is required for its use.

  The viscosity of the polyol (meth) acrylate mixture in the present invention is measured with a B-type viscometer, and is preferably 1 to 1900 mPa · s, more preferably 1 to 1700 mPa · s, and further preferably 1 to 1500 mPa · s at 25 ° C. It is. When the viscosity of the polyol (meth) acrylate mixture is out of the above range, it becomes difficult to handle as a liquid, and it is handled with heating to give appropriate fluidity, or a diluent (acrylic monomer, solvent, etc.) is used. Such use is not preferable because special care is required for its use.

  The polyol (meth) acrylate mixtures of the present invention are useful as polymerizable monomers in coating and ink compositions, and they can be cured by ultraviolet light, electron beams, etc., or by thermal means. When curing by ultraviolet rays or the like, generally known many types of photosensitizers or photopolymerization initiators are contained. The curing method can also be carried out according to known methods.

  The polyol (meth) acrylate mixture can be used alone or in combination with other monomers or polymers. Furthermore, this polyol (meth) acrylate mixture can also be polymerized by the addition of organic peroxides.

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.
The PII value and viscosity were measured by the following method.
It was measured by the PII value drape improvement method. That is, an adhesion test was performed on untreated skin of 6 healthy white rabbits whose back was shaved and on skin with scratches. The test site was divided into four locations, 0.5 ml of the sample was applied to a size of 1.5 × 1.5 inches, and fixed with a bandage. For irritation, erythema and edema were evaluated on a scale of 0 to 4, respectively. The total of the erythema and edema readings at 4, 24, and 48 hours after pasting was divided by 6 to give the individual rabbit a score, and the average of the six scores was taken as the PII value.
The viscosity was measured at 25 ° C. using a B-type viscometer (model BM, manufactured by Tokyo Keiki Seisakusho Co., Ltd.).

Production Example 1
TMP was synthesized from NBD and formaldehyde according to Example 1 described in JP-A-11-49708. After completion of the reaction, TMP was extracted using NBD as a solvent, and raw materials and by-products having a low boiling point were recovered and removed. Crude TMP obtained by extraction was distilled with a film evaporator. A polyol mixture having a composition of 8% TMP, 45% di-TMP, 28% bis-TMP, and 19% of other organic by-products was obtained as the residue in the distillation kettle from which TMP had been distilled off.

Production Example 2
The remaining 1300 parts by weight of the distillation still and 1300 parts by weight of acetone were added, and the mixture was heated and stirred until the solution became transparent. This was cooled to 30 ° C. with stirring, and crystallization was carried out for 2 hours while maintaining the temperature at 30 ° C. From the resulting slurry, 256 parts by weight of di-TMP crystals were separated by centrifugation, and acetone was distilled off from the resulting mother liquor to remove TMP 23%, di-TMP 26%, bis-TMP 25%, and other organic by-products 26%. Thus, 1044 parts by weight of a polyol mixture having the composition was obtained.

Example 1
In a 2000 ml round bottom flask equipped with a mechanical stirrer, temperature controller, thermometer, condenser and condenser, 285 parts by weight of the polyol mixture prepared in Production Example 2 (containing 24% by weight of hydroxyl group), 346% by weight of acrylic acid Parts, p-toluenesulfonic acid monohydrate 18 parts by weight, hydroquinone 3 parts by weight, phenothiazine 0.05 parts by weight, benzene 400 parts by weight, cyclohexane 100 parts by weight and heated to 82-90 ° C. Distilled and condensed together with the solvent, only water was discharged out of the system with a separator, and the solvent was returned to the reactor. When 72 parts by weight of water was generated, it was cooled to room temperature. The reaction mixture was dissolved in a mixture of 800 parts by weight of benzene and 200 parts by weight of cyclohexane, neutralized with a 20% aqueous sodium hydroxide solution, and then washed three times with 400 parts by weight of 20% brine. After distilling off the solvent under reduced pressure, it was treated with activated clay to obtain 419 parts by weight of a pale yellow polyol acrylate mixture. This product had a PII value of 1.8 and a viscosity of 400 mPa · s (25 ° C.). 5.0% by weight of 2-ethylanthraquinone (photosensitizer) is added to a portion of the product, and then the resulting sensitized clear coating composition is applied onto a steel panel and then the coating Was exposed to UV to obtain a transparent, dry film-like coating.

Example 2
The same operation as in Example 1 was carried out except that 279 parts by weight of the polyol mixture prepared in Production Example 1 (containing 24.5% by weight of hydroxyl group) was used. As a result, 415 parts by weight of a pale yellow polyol acrylate mixture was obtained. . This product had a PII value of 1.5 and a viscosity of 800 mPa · s (25 ° C.). 5.0% by weight of 2-ethylanthraquinone (photosensitizer) is added to a portion of the product, and then the resulting sensitized clear coating composition is applied onto a steel panel and then the coating Was exposed to UV to obtain a transparent, dry film-like coating.

Example 3
Using an apparatus similar to that described in Example 1, 285 parts by weight of a polyol mixture having the composition described in Production Example 1, 413 parts by weight of methacrylic acid, 3 parts by weight of p-toluenesulfonic acid, 3 parts by weight of hydroquinone, phenothiazine 0 .05 parts by weight and 500 parts by weight of toluene were charged and heated to 111 to 118 ° C., the produced water was distilled and condensed together with the solvent, and only water was discharged out of the system with a separator, and the solvent was returned to the reactor. When 72 parts by weight of water was generated, it was cooled to room temperature. The reaction mixture was dissolved in 1000 parts by weight of toluene, neutralized with a 20% aqueous sodium hydroxide solution, and then washed three times with 400 parts by weight of 20% brine. After the solvent was distilled off under reduced pressure, it was treated with activated clay to obtain 470 parts by weight of a pale yellow polyol methacrylate mixture. This product had a PII value of 0.4 and a viscosity of 100 mPa · s (25 ° C.). 5.0% by weight of 2-ethylanthraquinone (photosensitizer) is added to a portion of the product, and then the resulting sensitized clear coating composition is applied onto a steel panel and then the coating Was exposed to UV to obtain a transparent, dry film-like coating.

Comparative Example 1
A polyol mixture prepared in the same manner as in Production Example 1 except that simple distillation was used instead of distillation using a film evaporator, that is, a polyol having a composition of TMP 60%, di-TMP 16%, bis-TMP 11%, and other organic by-products 13%. Except that 228 parts by weight of the mixture (containing 30% by weight of hydroxyl group) was used, the same operation as in Example 1 was performed to obtain 377 parts by weight of a pale yellow polyol acrylate mixture. The PII value of this product was 3.0.

Comparative Example 2
A polyol mixture obtained by further heating and simple distillation of the polyol mixture obtained in Production Example 2, that is, a polyol mixture having a composition of 8% TMP, 12% di-TMP, 15% bis-TMP, and 65% of other organic by-products. Except for using 342 parts by weight (containing 20% by weight of hydroxyl group), the same operation as in Example 1 was performed to obtain 478 parts by weight of a pale yellow polyol acrylate mixture. The viscosity of this product was 3000 mPa · s (25 ° C.).

Claims (7)

  A polyol (meth) acrylate mixture obtained by esterification of a polyol mixture comprising ditrimethylolpropane, 2,2'-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol), and trimethylolpropane. The polyol (meth) acrylate mixture according to claim 1, wherein the composition of the polyol mixture satisfies the following conditions (a) to (c).
(A) The weight ratio of the total content of ditrimethylolpropane and 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) to the content of trimethylolpropane is 0.5 to A range of 20,
(B) The weight ratio of the content of 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) and the content of ditrimethylolpropane is in the range of 0.1-15. ,
(C) The total content of ditrimethylolpropane and 2,2′-methylenebis (oxymethylene) bis (2-ethyl-1,3-propanediol) is 30 to 95% by weight of the total polyol mixture.   Trimethylolpropane produced by the reaction of normal butyraldehyde and formaldehyde in the presence of a basic catalyst is extracted with a solvent, the solvent is distilled off from the resulting trimethylolpropane extract, and the resulting crude trimethylolpropane is obtained. The polyol (meth) acrylate mixture according to claim 1 or 2, wherein a residue obtained by distilling off trimethylolpropane, which is obtained when the product is purified by distillation, is used as the polyol mixture.   The polyol (meth) acrylate mixture according to any one of claims 1 to 3, wherein the primary skin irritation index is in the range of 0 to 2.0.   The polyol (meth) acrylate mixture according to any one of claims 1 to 4, wherein the viscosity at 25 ° C measured by a B-type viscometer is in the range of 1 to 1900 mPa · s.   Hardened | cured material formed by hardening | curing the composition containing the polyol (meth) acrylate mixture in any one of Claims 1-5.   An ink, a paint, an adhesive, or a casting material that uses a composition containing the polyol (meth) acrylate mixture according to any one of claims 1 to 5 as a raw material.