JPH0526809B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an alkyd resin containing a cellulose derivative and forming a coating film with excellent hardness, gloss, gasoline resistance, and weather resistance. Alkyd resin is a resin mainly composed of a condensate of polybasic acid and polyhydric alcohol, and is widely used in paints. Modified alkyd resins modified with other compounds are often used as alkyd resins, especially oil-modified alkyd resins in which fatty acids (oils) are added to the components. Cellulose derivatives such as nitrocellulose and cellulose acetate butyrate are added to this alkyd resin, and paints with excellent coating film hardness and gasoline resistance have been used for various purposes such as wood and metal. However, alkyd resins containing nitrocellulose have weather resistance problems such as yellowing of the paint film when used outdoors, and cellulose acetate butyrate is less compatible than nitrocellulose, which limits the composition of the alkyd resin to be mixed with. Therefore, it was difficult to obtain an alkyd resin with a sufficiently beautiful coating film. There are also cellulose-modified alkyd resins that use cellulose derivatives as alkyd resin components, but the hydroxyl groups of conventional cellulose derivatives are directly bonded to the cellulose skeleton, and there are many secondary hydroxyl groups in the hydroxyl groups, and Due to the presence of bulky substituents in the periphery, an alkyd resin sufficiently modified with a cellulose derivative could not be obtained. The present inventors aimed to solve these problems and obtain an alkyd resin containing a cellulose derivative that has excellent hardness, gloss, gasoline resistance, and weather resistance. The present inventors discovered that an alkyd resin using a graft polymer having a graft chain whose terminal end is a hydroxyl group obtained by ring-opening reaction of a cyclic ester as a component of a polyhydric alcohol improves the above-mentioned drawbacks, and completed the present invention. . That is, in the present invention, when producing an alkyd resin by reacting a polyhydric alcohol component and a polybasic acid component, a cyclic ester is subjected to a ring-opening reaction in the presence of a cellulose derivative having a hydroxyl group as a component of the polyhydric alcohol. The present invention provides a method for producing an alkyd resin characterized by using the obtained graft polymer. The alkyd resin of the present invention is not simply a mixture of a cellulose derivative and an alkyd resin, but the cellulose derivative is also chemically bonded as a component of the alkyd resin polymer molecule.Therefore, there is a problem of compatibility between the cellulose derivative and the alkyd resin. Moreover, since the graft polymer, which is a cellulose derivative used in the alkyd resin of the present invention, has a flexible graft chain formed by ring-opening of a cyclic ester, sufficient improvement can be achieved even without adding a plasticizer. Since it has flexibility and strength, the alkyd resin of the present invention forms a coating film that does not develop cracks even after a long period of time after being applied. The cellulose derivative used in the present invention may be any cellulose derivative having a hydroxyl group in the molecule, such as cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose sulfate, cellulose nitrate, etc. Examples include esters and cellulose ethers such as ethyl cellulose and benzyl cellulose. Among these cellulose derivatives, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, etc., which are industrially available, easy to handle, and have excellent weather resistance, are preferred. Note that these cellulose derivatives can be used alone or in combination of two or more. The cyclic ester used in the present invention may be one that can be polymerized by a ring-opening reaction using a known method, such as propiolactone, β-butyrolactone, α,α-bischloromethylpropiolactone, α, α-dimethyl-β-propiolactone, δ-valerolactone, β-ethyl-δ-valerolactone, 3,4,5-trimethoxy-δ-valerolactone, 1,4,-dioxan-2-one,
Glycolide, trimethylene carbonate, neopentyl carbonate, ethylene oxalate, propylene oxalate, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ
-Methyl-epsilon-caprolactone, epsilon-caprolactone, 4-methyl-7-isopropyl-epsilon-caprolactone, 3,3,5-trimethyl-epsilon-caprolactone, cis-disalicilide, trisalicilide, and the like. Among these cyclic esters, it is advantageous to use ε-caprolactone, which is industrially easily available, easy to handle, and has good compatibility with cellulose esters such as cellulose acetate butyrate, cellulose acetate propionate, and cellulose acetate. be. In the present invention, a graft polymer obtained by ring-opening reaction of a cyclic ester in the presence of a cellulose derivative having a hydroxyl group can be obtained by the following method. That is, in the presence of at least one of the above cellulose derivatives, a catalyst used for the ring-opening reaction of a cyclic ester, such as an organic acid, an inorganic acid,
Catalysts such as organic tin compounds, organic acid tin salts, alkali metals, organic compounds of alkali metals, alkylaluminiums, organic compounds of titanium, halides such as tin chloride (the catalysts used in the ring-opening reaction of cyclic esters are , written by Takeo Saegusa "Lecture on polymerization reaction theory 7. Ring-opening polymerization ()" P104-P128
(published by Kagaku Dojin Co., Ltd. in 1973). ), and if necessary, add an organic solvent such as xylene, generally at a temperature of 120 to 230℃ to 0.1 to 96
A method of reacting for about a period of time, that is, a method in which the applicant
57-197333. The graft polymer has a graft chain consisting of a cyclic lactone with a primary hydroxyl group at the end, and since this graft chain is relatively flexible, the graft polymer has the rigidity that is a feature of cellulose derivatives. It has both flexibility and flexibility due to the grafted chains. Moreover, since the graft polymer has a primary hydroxyl group that is more reactive than other alcoholic hydroxyl groups and is located away from the cellulose skeleton, the hydroxyl group is more reactive than the hydroxyl group directly bonded to the cellulose skeleton. It easily reacts with the functional groups, ie, carboxyl groups, and their derivatives, and the polycondensation reaction during the production of alkyd resins is carried out effectively. In the present invention, polyhydric alcohols commonly used in the production of alkyd resins can be used together with the above-mentioned graft polymers. For example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol, hexanediol,
Examples include glycerin, butanetriol, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerol, triglycerol, and the like. In addition, neopentyl glycol, neopentyl glycol ester of hydroxyhybaric acid, dipentaerythritol, 1,4-cyclohexanedimethanol, trimethylpentanediol, hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A, bisphenol A
Also included are propylene oxide adducts. The polybasic acids used in the present invention may be those commonly used in the production of alkyd resins, such as phthalic anhydride, isophthalic acid,
Examples include terephthalic acid, hydrogenated terephthalic acid, trimellitic anhydride, maleic anhydride, fumaric acid, adipic acid, sebacic acid, dotecanniic acid, hettic acid, and terpene maleic anhydride adducts. In addition to the above polybasic acids, a small amount of benzoic acid, P-
Monobasic acids such as tert-butylbenzoic acid may also be used. In the present invention, fatty acids (oils) commonly used in the production of alkyd resins together with graft polymers and polybasic acids, such as linseed oil, soybean oil, castor oil, dehydrated castor oil, olive oil, cottonseed oil, safflower oil, dimer acid, Tall oil, coconut oil, etc. may also be used. Furthermore, 1,2-epoxy aliphatic compounds, natural resins such as rosin, silicone resins, amino resins, etc. can also be used as appropriate as components of the alkyd resin of the present invention. In the method for producing an alkyd resin of the present invention, the graft polymer can be reacted with other components in any proportion to form an alkyd resin, but generally the graft polymer should be contained in an amount of 3 to 70% by weight. is preferable, and obtaining an alkyd resin by containing 10 to 30% by weight improves the hardness, gloss, and
It is particularly preferred because it provides a good balance of performance such as gasoline resistance. The alkyd resin of the present invention can be produced by any of the methods in which alkyd resins are generally produced, the melting method, and the solvent method. That is, the alkyd resin of the present invention can be produced by adding a polyhydric alcohol, a polybasic acid, and a fatty acid (oil) together and heating it, or by heating the fatty acid (oil) and a polybasic acid for exchange esterification (acidolysis). and then adding a polyhydric alcohol to esterify it, heating the fatty acid (oil) and polyhydric alcohol to perform exchange esterification (alcolysis), and then adding a polybasic acid to esterify it, etc. These methods are produced without a solvent or with the addition of a solvent, without a catalyst or with the addition of an esterification reaction catalyst, generally at temperatures between 60℃ and 320℃,
It can be produced by reaction for 1 hour to 72 hours, preferably 8 hours to 48 hours at 160 to 250°C. The alkyd resin of the present invention can be used alone or in combination with other resins as a coating resin. In addition, thinners, organic solvents, etc. that are normally added to paints, paint film drying rate regulators, plasticizers, leveling agents, crosslinking agents such as melamine compounds, polyisocyanate compounds, and epoxy compounds, and viscosity modifiers are added to the alkyd resin of the present invention. , dyes, pigments, etc. can be added as appropriate. The alkyd resin of the present invention is suitable for paints for metals, wood, ceramics, plastics, concrete, mortar, and the like. Next, further explanation will be given in Examples. Example 1 1 with stirrer, reflux condenser and thermometer
Tetrabutyl titanate in a glass flask
150g of ε-caprolactone containing 200ppm and thoroughly dried cellulose acetate (Daicel Chemical Co., Ltd.)
Co., Ltd.; LL-10) was charged, heated to 120°C, and sufficiently stirred under a nitrogen atmosphere to dissolve. Thereafter, the temperature was raised to 160°C and reaction was carried out for 16 hours to obtain a pale yellow graft polymer. Next, 100 g of the above graft polymer, 142 g of dehydrated castor oil, 33.3 g of p-tert-butylbenzoic acid, and tetrahydrophthalic anhydride were placed in a glass flask equipped with a stirrer, a reflux dehydrator, and a thermometer.
92.8g, isophthalic acid 16.6g, trimethylolpropane 20g and neopentyl glycol 43.7g
and conduct a dehydration esterification reaction at 200°C for 24 hours under a nitrogen atmosphere. Thus, the acid value is 18KOHmg/
g, and an alkyd resin having a hydroxyl value of 32 KOH mg/g was obtained. This was diluted with a mixed solvent of toluene/ethyl acetate (mixed weight ratio: toluene/ethyl acetate = 70/30) to a solid content of 55%, coated on a mild steel plate using a No. 30 bar coater, and then dried. Performance evaluation of the membrane was performed. The results are shown in Table 1. Example 2 1 with stirrer, reflux condenser and thermometer
Tetrabutyl titanate in a glass flask
150 g of ε-caprolactone containing 200 ppm and thoroughly dried cellulose acetate butyrate (manufactured by Eastman Chemical Company; CAB551-0.2)
Charge 150g of the solution, heat it to 120°C, stir thoroughly under a nitrogen atmosphere, and dissolve. After that, the temperature was raised to 160℃,
The reaction was carried out for 16 hours to obtain a pale yellow graft polymer. Next, 150 g of the above graft polymer was charged into a glass flask equipped with a stirrer, a reflux dehydrator, and a thermometer and heated to 180°C. This stuff under nitrogen atmosphere, neopentyl glycol 54.3
g, trimethylolpropane 20g, benzoic acid 22.8
g and 128 g of soybean oil were added, and the reaction was carried out at 200°C until the acid value became 5 or less. Next, 76.4 g of tetrahydrophthalic anhydride, 15.8 g of adipic acid, and 16.8 g of isophthalic acid are added, and a dehydration esterification reaction is further carried out at 210° C. for 24 hours. Thus, the acid value
An alkyd resin having a hydroxyl value of 12 KOH mg/g and a hydroxyl value of 24 KOH mg/g was obtained. This material was diluted with toluene to a solid content of 60%, and after coating on a mild steel plate using a No. 30 bar coater, the performance of the dried coating film was evaluated. The results are shown in Table 1.

【table】

[Table] Pencil hardness: Conducted according to JISK-5400 pencil drag test. Adhesion: Eleven vertical and horizontal lines were cut into the coating film at 1 mm intervals, cellophane adhesive tape was pressed onto each cut, and the number of lines remaining after the tape was peeled off was evaluated. Flexing resistance: A test piece was bent with the coating film on the outside to a bending diameter of 2 mm, and the condition of the coating film at this time was observed. Water resistance: The condition of the coating film was observed after 3 hours of immersion in 20°C water. Gasoline resistance: Clean the painted surface with absorbent cotton containing gasoline.
The condition after rubbing 100 times was evaluated. Ultraviolet resistance: The condition of the painted surface was observed after irradiating it with a 15W ultraviolet germicidal lamp from a distance of 15cm for 48 hours.

Claims (1)

[Claims] 1. When producing an alkyd resin by reacting a polyhydric alcohol component and a polybasic acid component, a graft polymer obtained by ring-opening a cyclic ester in the presence of a cellulose derivative having a hydroxyl group as a component of the polyhydric alcohol is used. A method for producing an alkyd resin characterized by using coalescence.