JP5829989B2 - Polyglycerol resin plasticizer and thermoplastic resin composition containing the same - Google Patents

Description

  The present invention relates to a polyglycerin-based resin plasticizer composed of polyglycerin and 2-ethylhexanoic acid, and a thermoplastic resin composition excellent in flexibility and bleed resistance containing the same.

  In recent years, from the viewpoint of protecting the natural environment, polyester resins and polylactic acid resins are often used in applications such as containers and packaging materials. On the other hand, polyvinyl butyral resins are used and studied as laminated glass interlayers and solar cell encapsulants for automobiles and buildings, and ionomer resins are used as containers, packaging materials, solar cell encapsulants, etc. ing. Generally, since these resins lack flexibility when applied to films, sheets and the like, the use of plasticizers has been studied for the purpose of facilitating processing and imparting flexibility to molded products. However, since these resins all have high processing temperatures, a highly volatile plasticizer reduces the amount of plasticizer remaining in the resin composition, causing problems in performance and physical properties, and in terms of work environment. But it becomes a problem. Therefore, a plasticizer that satisfies both compatibility and heat resistance has been demanded.

  Generally, as a plasticizer used for a polyester resin or a polylactic acid resin, triacetin (Patent Document 1), acetylated monoglyceride having an acyl group having 8 to 14 carbon atoms (Patent Document 2), polyglycerin acetate (Patent Document 3) ) And the like are disclosed, but none of them are satisfactory because of poor heat resistance. Further, phthalic acid derivatives such as dioctyl phthalate (Patent Document 4) are also disclosed, but safety has been pointed out due to problems such as environmental hormones.

  On the other hand, triethylene glycol 2-ethylhexanoic acid ester (Patent Document 5) is disclosed as a plasticizer used for polyvinyl butyral resin, and diglycerin is used as a plasticizer used for ionomer resin. Monocaprylic acid ester, diglycerin monodistearic acid ester, polypropylene glycol and the like are disclosed (Patent Document 6). These plasticizers have good heat resistance and compatibility, but when the amount of plasticizer is increased or when exposed to harsh environments, the bleed resistance may decrease, There was a need for better compatibility.

Japanese Patent Application Laid-Open No. 07-177826 JP 2002-053742 A JP 2008-296482 A JP 2000-198908 A JP 2011-042552 A JP 2009-035699 A

  In view of such circumstances, the present invention provides a plasticizer that has excellent heat resistance that does not volatilize even at high temperatures and has good compatibility with the resin, and heat that is excellent in flexibility and bleed resistance. It aims at providing a plastic resin composition.

  In order to solve the above-mentioned problem, as a result of intensive studies by the present inventors, a polyglycerin having an average degree of polymerization calculated from a hydroxyl value of 2 to 10 and 2-ethylhexanoic acid is used. The present inventors have found that the above problems can be solved by using glycerin 2-ethylhexanoic acid ester. Furthermore, in the said polyglycerol 2-ethylhexanoic acid ester, it discovered that the thermoplastic resin composition which has a more superior function can be provided by a solubility parameter (SP value) being 9.0 to 12.5. .

  By blending the polyglycerin 2-ethylhexanoate of the present invention with a thermoplastic resin, the glass transition temperature can be efficiently lowered and the melt index can be improved moderately. Since it is not seen at all and has excellent compatibility, the desired reforming performance can be maintained for a long time without causing deterioration of performance over time or quality change.

  The present invention is described in detail below. However, parts and% are based on weight unless otherwise specified.

As the polyglycerol of polyglycerol 2-ethylhexanoate used in the present invention, one having an average degree of polymerization of 2 to 10 calculated from the hydroxyl value is used. Moreover, the polyglycerol of this range may be used independently, or 2 or more types may be used together. Here, the average degree of polymerization is the average degree of polymerization (n) of polyglycerin calculated from the hydroxyl value by end group analysis. Specifically, the average degree of polymerization is calculated from the following formulas (Formula 1) and (Formula 2).
(Formula 1) Molecular weight = 74n + 18
(Formula 2) Hydroxyl value = 56110 (n + 2) / Molecular weight The hydroxyl value in the above (Formula 2) is a numerical value that serves as an index of the number of hydroxyl groups contained in polyglycerin, and is contained in 1 g of polyglycerin. The number of milligrams of potassium hydroxide required to neutralize the acetic acid required to acetylate the hydroxyl group. The number of milligrams of potassium hydroxide is calculated according to the Japan Oil Chemists 'Society edited by “The Japan Oil Chemists' Society, Standard Oil Analysis Test Method (I), 2003 edition”.

  Moreover, in the polyglycerin having an average degree of polymerization calculated from the hydroxyl value of 2 to 10 except for diglycerin having an average degree of polymerization of 2, generally a composition having a molecular weight distribution is used. Two or more of these polyglycerols having different molecular weight distributions may be mixed, and if the average degree of polymerization calculated from the hydroxyl value of the polyglycerol mixture is 2 to 10, the average degree of polymerization is less than 2, and 10 More than polyglycerol can be used.

  The polyglycerin 2-ethylhexanoic acid ester used in the present invention is composed of 2-ethylhexanoic acid, which is a branched alkanoic acid having 8 carbon atoms, and preferably has a purity of 95% or more. In addition, octylic acid (made by Kyowa Hakko Chemical Co., Ltd.) etc. are mentioned as an example of such a commercial item of 2-ethylhexanoic acid.

The solubility parameter (SP value) of the polyglycerol 2-ethylhexanoic acid ester of the present invention is in the range of 9.0 to 12.5, preferably 9.0 to 11.0, more preferably 9.0. The range is 10.0. The solubility parameter here can be calculated by the method (Fedors method) described in “Polymer Engineering and Science, Vol. 14, No. 2, p 147-154 (1974)”. The SP value can be expressed by the following equation.
SP value (δ) = (ΔH / V) ^1/2
In the formula, ΔH represents the heat of vaporization (cal), and V represents the molar volume (cm ³ ). Further, as ΔH and V, the total heat of molar evaporation (ΔH) and the total volume (V) of the atomic groups described in pages 151 to 153 of the above-mentioned document can be used. Those having a close numerical value are easy to mix with each other (high compatibility), and those having a close numerical value are indices that indicate that they are difficult to mix. In polyglycerin 2-ethylhexanoic acid ester, when the SP value is less than 9.0 and exceeds 12.5, the compatibility with the resin is lowered and bleeding occurs over time, which is not preferable. .

The esterification rate of the polyglycerol 2-ethylhexanoic acid ester of the present invention is preferably 20 mol% or more, more preferably 50 mol% or more. Outside this range, the compatibility with the resin tends to decrease, and the plasticizer may bleed. Here, the esterification rate is the average degree of polymerization of polyglycerol (n) calculated from the hydroxyl value by end group analysis, the number of hydroxyl groups of this polyglycerol (n + 2), and 2-addition to polyglycerol. When the number of moles of ethylhexanoic acid is (M), (M / (n + 2)) × 100 = a value calculated by esterification rate (%). The hydroxyl value is a numerical value that is an index of the number of hydroxyl groups contained in polyglycerol, and is required to neutralize acetic acid necessary for acetylating free hydroxyl groups contained in 1 g of polyglycerol. The number of milligrams of potassium hydroxide. The number of milligrams of potassium hydroxide is calculated according to the Japan Oil Chemists 'Society edited by “The Japan Oil Chemists' Society, Standard Oil Analysis Test Method (I), 2003 edition”. Moreover, an average degree of polymerization is an average degree of polymerization (n) of the polyglycerol calculated from the hydroxyl value by a terminal group analysis method. Specifically, the average degree of polymerization is calculated from the following formulas (Formula 1) and (Formula 2).
(Formula 1) Molecular weight = 74n + 18
(Formula 2) hydroxyl value = 56110 (n + 2) / molecular weight

  The polyglycerol 2-ethylhexanoic acid ester of the present invention preferably has a weight reduction rate of 5% by weight or less when the temperature is raised from 25 ° C. to 200 ° C. at a rate of 5 ° C. per minute. When the weight reduction rate exceeds 5% by weight, the amount of volatilization increases when performing melt-kneading with the thermoplastic resin, and the residual amount of plasticizer in the resin composition decreases, causing problems in performance and physical properties. there is a possibility. Moreover, since there is a possibility of problems such as odor filling due to volatile components in terms of the working environment, it is necessary to keep it within this range.

  The polyglycerol 2-ethylhexanoic acid ester of the present invention is synthesized by a general esterification reaction. As an example, the reaction is allowed to proceed while heating to a reaction temperature of 160 ° C. or higher under synthesis conditions equipped with a reflux apparatus and removing the produced water out of the system.

  The polyglycerin 2-ethylhexanoic acid ester of the present invention can be synthesized without a catalyst or in the presence of a catalyst. Examples of catalysts that can be used include basic catalysts and acidic catalysts. As the basic catalyst, sodium hydroxide, potassium hydroxide and the like are preferable. The acidic catalyst is preferably (ortho) phosphoric acid, polyphosphoric acid, and acidic phosphoric acid esters such as 2-ethylhexyl acid phosphate, oleyl acid phosphate, stearyl acid phosphate, and these are used alone. Two or more types may be used in combination. In addition, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, stannous chloride, stannic chloride, dibutyltin bis (2-ethylhexanoate), dibutyltin diacetate, tetraethoxytitanium, tetraisopropoxytitanium, etc. Although it is mentioned, it is not limited to these.

  The present invention also provides the above-mentioned polyglycerin 2-ethylhexanoic acid ester and also provides a thermoplastic resin containing the same. The content ratio of the polyglycerin 2-ethylhexanoic acid ester to be blended as the plasticizer component is preferably 1 to 60 parts by weight and more preferably 3 to 40 parts by weight with respect to 100 parts by weight of the thermoplastic resin. preferable. If the content ratio of polyglycerin 2-ethylhexanoic acid ester is less than 1 part by weight, the plasticizing effect is not sufficiently exerted, and if it exceeds 60 parts by weight, the mechanical properties of the thermoplastic resin composition are lowered. This range is preferred.

  The thermoplastic resin used in the thermoplastic resin composition of the present invention is preferably a polymer having a polar group in its structure. Typical examples include, but are not limited to, a polyester resin, a polylactic acid resin, a polyvinyl butyral resin, an ionomer resin, a polyvinyl chloride resin, a polycarbonate resin, and a resin in which several of these are combined.

  In the thermoplastic resin composition of this invention, the plasticizer different from polyglycerol 2-ethylhexanoic acid ester can also be contained. As a plasticizer, glycerin fatty acid esters such as glycerin diacetomonocaprylate, glycerin diacetomonolaurate, glycerin 2-ethylhexanoic acid monoester, glycerin 2-ethylhexanoic acid diester, glycerin 2-ethylhexanoic acid triester, Examples include polyethylene glycol fatty acid esters such as triethylene glycol 2-ethylhexanoate, tetraethylene glycol 2-ethylhexanoate, and pentaethylene glycol 2-ethylhexanoate. Moreover, these plasticizers can be used alone or in combination of two or more. In addition, by blending polyglycerin 2-ethylhexanoate, glycerin fatty acid esters, and polyethylene glycol fatty acid esters, the compatibility is excellent and bleed resistance can be maintained over a long period of time.

  Plasticizers that can be used in the thermoplastic resin composition of the present invention include general plasticizers such as polyester plasticizers represented by dioctyl phthalate, diisononyl phthalate, tributyl acetyl citrate, and adipic acid ester in addition to the above-mentioned ones. Can also be used.

  In the thermoplastic resin composition of the present invention, various additives such as an antioxidant, an ultraviolet absorber, an infrared absorber, a thermal stabilizer, a light stabilizer, and the like, as long as the object of the present invention is not impaired. A colorant, a foaming agent, a flame retardant, a fluorescent brightening agent, an antistatic agent, a filler, and the like can be appropriately blended.

  There is no restriction | limiting in particular as a preparation method of the resin composition of this invention, A conventionally well-known method can be used. For example, the resin composition can be prepared by a melt-kneading method or a method of dissolving and mixing in a solvent. Among these methods, the melt-kneading method is preferable. When this melt-kneading method is applied, a thermoplastic resin, the polyglycerin 2-ethylhexanoic acid ester of the present invention, and various additives used as required are blended, and a single-screw extruder, a multi-screw extruder, a kneader It is preferable to melt knead at a temperature of 80 ° C. or higher using a bumper mixer or the like.

  As an index of flexibility of the thermoplastic resin composition of the present invention, glass transition temperature (Tg) and melt index (MI value) can be used. Of these, the glass transition temperature is preferably lowered as compared with the case where no plasticizer is contained, and the greater the reduction width, the higher the flexibility imparting effect. On the other hand, the melt index is preferably increased as compared with the case where no plasticizer is contained, and it is desired that the melt index has a moderate increase range. Moreover, the suitable range of each numerical value changes with kinds and uses of resin.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited only to these Examples. The polyglycerin used in this synthesis is diglycerin, triglycerin, tetraglycerin, hexaglycerin, decaglycerin (all manufactured by Sakamoto Pharmaceutical Co., Ltd.), and the average degree of polymerization calculated from the hydroxyl value is They are 2, 3, 4, 6, 10 respectively. In addition, octylic acid (manufactured by Kyowa Hakko Chemical Co., Ltd.) was used as 2-ethylhexanoic acid. Further, polyvinyl butyral resin, polylactic acid resin, and ethylene ionomer resin were used as the thermoplastic resin. Examples of the present invention and comparative examples are shown below. However, “%” is based on weight unless otherwise specified.

(Measurement of glass transition temperature of thermoplastic resin composition)
About the thermoplastic resin composition which melt-kneaded various plasticizers, the glass transition temperature (Tg) was measured using the differential scanning calorimeter (Thermo Plus DSC8320, product made by RIGAKU). 5 mg each of the sample and α-alumina as a control substance were weighed into an aluminum sample cell, heated from room temperature to 200 ° C. at a rate of 5 ° C. per minute in a nitrogen atmosphere, and then increased to −50 ° C. at a rate of 5 ° C. per minute. The glass transition temperature is obtained from the intersection of the tangent line of the endothermic curve and the extension line of the baseline when the temperature is raised to 200 ° C at a rate of 5 ° C per minute. It was. In addition, the glass transition temperature of the thermoplastic resin which does not contain the polyglycerin 2-ethylhexanoic acid ester of this invention was 75 degreeC for polyvinyl butyral resin, 60 degreeC for polylactic acid resin, and 95 degreeC for ethylene-type ionomer resin.

(Measurement of melt index value of thermoplastic resin composition)
About the thermoplastic resin composition, MI value (melt index value) was measured using MELT INDEXER TYPE C-5059D (made by Toyo Seiki Seisakusho). Measurement was performed according to JIS K-7210 under the conditions of 10.0 g of sample, preheating time of 360 seconds, test time of 600 seconds, test temperature of 190 ° C., test load of 2.16 kgf, and method A (CUTT OFF method). The melt index of the thermoplastic resin containing no polyglycerin 2-ethylhexanoic acid ester of the present invention is 5.5 g / 10 min for polyvinyl butyral resin, 9.4 g / 10 min for polylactic acid resin, and 10 for ethylene ionomer resin. 0.0 g / 10 min.

(Plasticizer bleed test of thermoplastic resin composition)
Further, the thermoplastic resin composition was visually evaluated for the presence or absence of bleeding of the plasticizer when left at 25 ° C. for 1 month and then at 10 ° C. for 1 month. No bleed at 25 ° C. or 10 ° C., no bleed at 25 ° C., slightly bleed at 10 ° C., no bleed at 25 ° C., 10 ° C. The case where bleeding occurred was evaluated as Δ, and the case where plasticizer bleeding occurred at 25 ° C. was evaluated as ×. Then, the evaluated thermoplastic resin composition was judged as a preferred example.

(Synthesis Example 1)
A reactor equipped with a thermometer, a stirrer, a nitrogen blowing tube, and a Dean-Stark reflux device was charged with 317.7 g of polyglycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd., diglycerin) and 551.2 g of 2-ethylhexanoic acid, An esterification reaction was performed at 200 to 250 ° C. while blowing a certain amount of nitrogen and stirring. As a result, the hue was APHA20, the acid value was 0.1 mgKOH / g, the hydroxyl value was 268.5 mgKOH / g, the esterification rate was 50 mol%, the thermal weight loss at 200 ° C. was 2.8 wt%, and the SP value was 10. 7 polyglycerin 2-ethylhexanoic acid ester (abbreviation: 2G2EH) was obtained.

(Synthesis Examples 2 to 18)
Various ester compounds were synthesized in the same manner as in Synthesis Example 1 except that the type of polyglycerin or polyhydric alcohol, the type of fatty acid, and the amounts charged were changed. The obtained results are shown in Tables 1 and 2.

Example 1
30.0 g of polyglycerol 2-ethylhexanoic acid ester (abbreviation: 2G2EH) obtained in Synthesis Example 1 is added to 100.0 g of polyvinyl butyral resin, and melt-kneaded at 190 ° C. using a twin screw extruder. The polyvinyl butyral resin composition was obtained by performing. The resin composition had a Tg of 10 ° C. and a melt index of 28 g / 10 min. No plasticizer bleed was observed at any of 10 ° C. and 25 ° C., and the evaluation was good.

(Examples 2 to 15 and Comparative Examples 1 to 13)
The thermoplastic resin composition was adjusted and evaluated in the same manner as in Example 1 except that the type of thermoplastic resin and the type and amount of plasticizer were changed. The obtained results are shown in Tables 3 and 4.

  In the present invention, a thermoplastic resin to which a polyglycerin fatty acid ester composed of polyglycerin having an average degree of polymerization calculated from a hydroxyl value of 2 to 10 and 2-ethylhexanoic acid is added, and further, the polyglycerin fatty acid ester And a thermoplastic resin to which glycerin 2-ethylhexanoate and / or polyethylene glycol 2-ethylhexanoate is added to the thermoplastic resin, the glass transition temperature is efficiently reduced, and the melt index It was found that the desired reforming performance can be maintained for a long time without causing bleed at all under long-term storage conditions and without causing deterioration in performance over time or change in quality.

  Although the cause of the effect of the present invention has not been clarified, a polyglycerin skeleton is obtained by controlling to a specific esterification rate or a specific SP value using a polyglycerin having an average degree of polymerization of 2 to 10. It is considered that the polarity of the ether bond portion in the inside influences and shows excellent compatibility with a thermoplastic resin partially having a polar group and a modification effect.

  By blending the polyglycerin 2-ethylhexanoate of the present invention with a thermoplastic resin, the glass transition temperature can be efficiently lowered and the melt index can be improved moderately. Since it is not seen at all and has excellent compatibility, it can maintain desired reforming performance for a long time without causing deterioration of performance over time or quality change, and various films / sheets, plastic molding It can be applied in applications such as goods.

Claims (6)

  Polyglycerin 2-ethylhexanoic acid ester composed of polyglycerin having an average degree of polymerization calculated from a hydroxyl value of 2 to 10 and 2-ethylhexanoic acid, and a solubility parameter (SP value) from 9.0. A resin plasticizer characterized by being 12.5.   The resin plasticizer according to claim 1, wherein the polyglycerin 2-ethylhexanoic acid ester has an esterification rate calculated from a hydroxyl value of 20 mol% or more.   The weight reduction rate when the polyglycerin 2-ethylhexanoic acid ester is heated from 25 ° C to 200 ° C at a rate of 5 ° C per minute is 5% by weight or less. The resin plasticizer described in 1.   A thermoplastic resin composition comprising the resin plasticizer according to any one of claims 1 to 3 and a thermoplastic resin.   Furthermore, glycerin 2-ethylhexanoic acid ester and / or polyethyleneglycol 2-ethylhexanoic acid ester are contained, The thermoplastic resin composition of Claim 4 characterized by the above-mentioned. The thermoplastic resin composition according to claim 4 or 5, wherein the thermoplastic resin is one or more selected from a polyester resin, a polylactic acid resin, a polyvinyl butyral resin, and an ionomer resin.