JPH0414703B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a light-colored unsaturated polyester resin with significantly improved coloration. (Prior art) Unsaturated polyester resins obtained by reacting an alcohol component with an acid component containing an α,β-unsaturated dibasic acid and/or its acid anhydride and, if necessary, a polybasic acid, are mainly produced by This is dissolved in vinyl monomer and used as an unsaturated polyester resin composition for various purposes. For example, if necessary, peroxides, accelerators, photosensitizers, etc. are added to this unsaturated polyester resin composition, and the composition is cured with heat or light to produce cast products such as buttons and ornaments, wood, etc. Used as a protective film for plywood, etc. In addition, this unsaturated polyester resin composition is impregnated into a fibrous reinforcing material such as glass fiber, carbon fiber, or organic fiber, and in some cases, a compound prepared by mixing a filler with the unsaturated polyester resin composition is used for fibrous reinforcement. By impregnating the material and curing it with light or heat as in the previous case, it can be used as ERP for corrugated sheets, bathtubs, etc.
Used in septic tanks, tanks, kitchen counters, etc. Among these uses, hue and transparency are major factors that increase product value for cast products such as buttons, corrugated sheets, bathtubs, kitchen counters, etc. Therefore, unsaturated polyester resin is used. It is required that the material be uncolored and transparent. Alternatively, unsaturated polyester resin can be obtained by dissolving unsaturated polyester resin in various solvents and impregnating it into a sheet-like base material such as glass fiber cloth or paper to form a prepreg and curing it, or by dissolving unsaturated polyester resin in vinyl monomer. The resin composition is impregnated into a sheet-like base material such as glass fiber cloth or paper, and when it is cured, it is not colored and has a strong transparency even when used as a decorative board or laminate for furniture, furnishings, or electrical appliances. Unsaturated polyester resins are prized. Generally, when an unsaturated polyester resin is synthesized by a conventional method, a yellow colored resin is obtained, and various attempts have been made to prevent this coloration. For example, known methods for preventing discoloration of unsaturated polyester resins include lowering the temperature during synthesis and adding various phosphorus compounds during synthesis. However, methods of lowering the synthesis temperature
This is undesirable because it increases the synthesis time and leads to a decrease in productivity. In addition, in the method of using various phosphorus compounds during synthesis, the phosphorus compounds generally serve as a curing retardant when an unsaturated polyester resin composition is cured with a peroxide such as methyl ethyl ketone peroxide and an accelerator such as cobalt naphthenate. It is well known that unsaturated polyester resins synthesized by this method and unsaturated polyester resin compositions using the same have a limited range of use due to delayed curing. In addition, if a phosphorus compound is used within a range that does not cause curing delay, there is a limit to the amount added, and there are disadvantages such as not being able to fully exert the effect of preventing coloring, which is not a preferred method of preventing coloring. It's hard to say. On the other hand, even if the unsaturated polyester resin is slightly yellow colored, a blue dye, fluorescent whitening agent, etc. has been added as a bluing agent at the stage of preparing the unsaturated polyester resin composition. However, when a blue dye is added, the resin has a bluish tint and the yellow coloring appears to disappear, but the transparency of the resin composition decreases, which is not preferable. Furthermore, in the method of adding a fluorescent brightener, the color of the brightener changes significantly due to light and heat, and the effect is only temporary, so this method cannot be said to be a preferable method either. (Objective of the Invention) The present invention was made in view of the current situation, and it not only prevents coloring of unsaturated polyester resins, but also creates a non-container that does not adversely affect the curability of the resulting unsaturated polyester resin composition. The purpose of the present invention is to provide a method for producing saturated polyester resin. (Structure of the Invention) The present invention provides a method for reacting an alcohol component with an acid component containing an α,β-unsaturated dibasic acid and/or its acid anhydride and another polybasic acid. The present invention relates to a method for producing an unsaturated polyester resin characterized by the presence of a keto-enol tautomer. (However, R and R' are unsubstituted or substituted monovalent hydrocarbon groups, and R and R' may be the same or different.) R and R' in formula () are unsubstituted or a substituted monohydric hydrocarbon group, and R and R' may be the same or different. Here, as the unsubstituted monovalent hydrocarbon group,
Examples include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, and octyl group, phenyl group, cycloalkyl group, and aralkyl group. Examples of substituted monovalent hydrocarbon groups include halogen-substituted hydrocarbon groups such as trifluoromethyl group. A specific example of the keto-enol tautomer represented by the formula () is astylacetone.

【formula】 benzoylacetone

[Formula] 2,2,6,6-tetramethyl-3,5-heptanedione dibenzoylmethane 1,1,1-trifluoro-2,4-pentanedione etc. The above-mentioned keto-enol tautomer is present when the above-mentioned acid component and alcohol component are reacted, and is preferably added to the system at the beginning of the synthesis of the unsaturated polyester resin described below or at an early stage of the synthesis. Ru. Further, the amount added is preferably in the range of 0.001 part to 1 part by weight per 100 parts by weight of the initial charge amount of acid component and alcohol component.
More preferably, the amount is in the range of 0.005 to 0.05 parts by weight. Examples of the α,β-unsaturated dibasic acid and/or its acid anhydride include maleic acid, fumaric acid, itaconic acid, citraconic acid, and maleic anhydride. Two or more of these may be used in combination. Other polybasic acids include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, trimellitic anhydride, succinic acid, azelaic acid, adipic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, and hexahydrophthalic acid. , hexahydrophthalic anhydride, rosin-maleic anhydride adduct, etc. can be used. Using halogenated polybasic acids such as chlorinated polybasic acids such as Hetts' acid, Hetts' anhydride, tetrachlorophthalic acid, and tetrachlorophthalic anhydride, and brominated polybasic acids such as tetrabromophthalic acid and tetrabromophthalic anhydride. I can do it. Two or more of these may be used in combination. Alcohol components include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin,
Trihydric alcohols such as trimethylolpropane, tetrahydric alcohols such as pentaerythritol, etc. can be used. It is also possible to use halogenated alcohols such as chlorinated and brominated alcohols of the various alcohols mentioned above. Other basic acids include halogenated polybasic acids,
It is preferable to use a halogenated alcohol as the alcohol component. Two or more of these may be used in combination. The production method for obtaining unsaturated polyester resin by reacting the above acid component and alcohol component is mainly carried out by proceeding with a condensation reaction, and low molecules such as water produced when both components react are removed from the system. Proceed by letting go. A general apparatus and reaction conditions for carrying out this reaction will be explained. The reaction equipment is made of glass, stainless steel, or other material that is inert to acid components, a stirring device, a fractionator to prevent distillation of the alcohol component due to azeotropy between water and the alcohol component, and a temperature control system for the reaction system. It is preferable to use a reaction apparatus equipped with a heating device for increasing the temperature, a temperature control circuit for the heating device, and a blowing device for nitrogen gas or the like. The reaction conditions are preferably a temperature of 150° C. or higher at which the reaction rate is sufficiently high. To prevent coloring due to oxidation reactions at high temperatures, the temperature should be between 160°C and 210°C.
A range of 0.degree. C. is more preferred. Furthermore, in order to prevent side reactions due to oxidation at high temperatures, it is preferable to carry out the synthesis while passing an inert gas such as nitrogen or carbon dioxide. The reaction proceeds by heating a system in which an acid component and an alcohol component are mixed, and removing low-molecular compounds such as condensed water produced from the system. This is preferably carried out by natural distillation by passing an inert gas through the system. ,
Or by distillation under reduced pressure. Furthermore, if the low molecular weight compound to be distilled has a high boiling point, a high vacuum is required. Furthermore, in order to promote the distillation of low-molecular compounds such as condensed water, a solvent such as toluene or xylene can be added to the system as an azeotropic component to perform natural distillation. The progress of the reaction can generally be determined by measuring the amount of distillate produced by the reaction, quantifying the terminal functional group, and measuring the viscosity of the reaction system. The synthesized unsaturated polyester resin is dissolved in polymerizable monomers such as styrene, vinyltoluene, divinylbenzene, methyl methacrylate, and vinyl acetate to form an unsaturated polyester resin composition.
In addition, various additives such as a polymerization inhibitor such as hydroquinone, a polymerization accelerator such as cobalt naphthenate, a photosensitizer such as benzophenone, and a peroxide may be added as necessary. allyl glycidyl ether,
It is also possible to modify unsaturated polyester resins using phenyl glycidyl ether and the like. (Example) The present invention will be explained below with reference to Examples. Parts indicate parts by weight. Example 1 152 parts of propylene glycol, 98 parts of maleic anhydride, 148 parts of phthalic anhydride, and 0.04 parts of benzoylacetone were charged into a four-neck flask equipped with a stirring bar, a condenser, a nitrogen gas inlet tube, and a thermometer. While slowly flowing nitrogen gas, the temperature is raised to 150°C over 1 to 1.5 hours using a mantle motor. Furthermore, the temperature was raised to 200℃ for 4 hours,
Keep warm at that temperature. After about 12 hours, acid value 32
An unsaturated polyester resin was obtained. Further temperature
Lower the temperature to 100℃ and add hydroquinone as a polymerization inhibitor.
0.05 parts and 160 parts of styrene were added to obtain an unsaturated polyester resin composition. The hue of this unsaturated polyester resin composition was 80 in Hazen color number. In addition, this unsaturated polyester resin composition is
6°C for the unsaturated polyester resin composition
When the gel was cured using 0.5% by weight of % cobalt naphthenate and 1% by weight of 55% methyl ethyl ketone peroxide, the gel time until curing was 12 minutes. Example 2 Using the same equipment as in Example 1, 136 parts of ethylene glycol, 98 parts of maleic anhydride, 389 parts of hectate,
0.06 part of Karenz DK-2 (dibenzoylmethane; manufactured by Showa Denko K.K.) was charged, the temperature was raised to 170℃ in 2 hours, the temperature was kept at this temperature, and unsaturated polyester resin with an acid value of 20 was added over 15 hours. Obtained. Further temperature
Lower the temperature to 100℃, add 0.09 parts of hydroquinone, and styrene.
255 parts were added to obtain an unsaturated polyester resin composition. The hue of this unsaturated polyester resin composition is
It had a Hazen color number of 60. Comparative Example 1 Using the same synthesis apparatus as in Example 1, 152 parts of propylene glycol, 98 parts of maleic anhydride, and 148 parts of phthalic anhydride were charged, and an unsaturated polyester resin with an acid value of 28 was produced by the same synthesis process as in Example 1. Obtained.
As in Example 1, the temperature was lowered to 100°C and 0.05 part of hydroquinone and 160 parts of styrene were added to prepare an unsaturated polyester resin composition, and the hue was 120 on the Hazen color number. Comparative Example 2 Using the same synthesis apparatus as in Example 1, 136 parts of ethylene glycol, 98 parts of maleic anhydride, and 389 parts of hexate
Using the same synthesis process as in Example 2, an unsaturated polyester resin with an acid value of 25 was obtained. moreover,
Similarly, 0.09 part of hydroquinone, styrene
255 parts were added to obtain an unsaturated polyester resin composition. The hue of this unsaturated polyester resin composition was 400 in Hazen color number. (Effects of the invention) The production method of the invention significantly reduces coloring,
A light-colored unsaturated polyester resin with strong transparency can be obtained.

Claims (1)

[Claims] 1. When reacting an acid component containing an α,β-unsaturated dibasic acid and/or its acid anhydride with another polybasic acid and an alcohol component, - A method for producing a light-colored unsaturated polyester resin characterized by the presence of an enol tautomer. (However, R and R' are unsubstituted or substituted monovalent hydrocarbon groups, and R and R' may be the same or different.) 2. When other polybasic acids are halogenated A method for producing a light-colored unsaturated polyester resin according to claim 1, which is a polybasic acid. 3. The method for producing a light-colored unsaturated polyester resin according to claim 1, wherein the alcohol component is a halogenated alcohol.