JP4653098B2 - Biodegradable polyester solution - Google Patents

Description

  The present invention relates to a biodegradable polyester solution that can be used for adhesion, adhesion, printing, coating, and the like.

  Recently, attention has been focused on biodegradable polyesters, as global environmental cleanup and sustainable development of the earth have become global concerns. Although they are beginning to be used as films and as molded products, they are used in some cases, but may be subjected to processing such as adhesion, adhesion, printing, and coating in practical use. Originally, the adhesives, pressure-sensitive adhesives, inks, and coating agents used in these processes should also be derived from biodegradable resins, but in practice, conventional resins, that is, non-biodegradable resins are mainly used. The raw material is used.

  Indeed, solutions and colloids of natural polymer substances such as starch, casein, shellac and rubber latex are biodegradable and have been used as adhesives, adhesives or coating agents for a long time. More recently, water-dispersed products of biodegradable resins such as polylactic acid and polybutylene succinate have begun to appear on the market. However, they are often insufficient in terms of adhesive strength, adhesive strength, etc., and water resistance often required in practice. The main causes are considered to be the presence of an emulsifier used for water dispersion and to keep the molecular weight of the biodegradable resin small in order to facilitate water dispersion. Further, it is unsuitable for food processing adhesives, pressure-sensitive adhesives, and coating agents, which are expected to be used for biodegradable resins, due to the presence of these emulsifiers.

  Therefore, adhesives, pressure-sensitive adhesives, inks, coating agents and the like that are biodegradable and practically excellent in performance such as adhesive strength, adhesion strength, and water resistance have not been obtained.

  If an organic solvent solution of a biodegradable resin can be used, it is considered that the above-mentioned problems can be overcome to a considerable extent such as the use of an emulsifier can be avoided. However, the biodegradable resin is hardly soluble in organic solvents except for polycaprolactone, and is only slightly soluble in chlorine-containing hydrocarbon organic solvents (chloroform, dichloroethane, hexafluoroisopropanol, etc.). Organic solvents containing halogens (called halogen solvents), such as chlorine-containing hydrocarbon organic solvents, accumulate in the global environment without being metabolized by living organisms such as microorganisms, and have an adverse effect on the global environment. It also adversely affects the safety of living things. Therefore, a biodegradable polyester solution using a halogen-free organic solvent (referred to as a non-halogen solvent), especially an industrial general-purpose non-halogen solvent (hereinafter referred to as a general-purpose non-halogen solvent), which is less problematic in terms of global environment and safety. This is a problem.

  The prior art for this is (A) limiting the number average molecular weight of the biodegradable resin to 15,000 or less, and compensating for the performance degradation caused by the combined use of the crosslinking agent (JP-A-8-31368), ( B) The ratio of L-form / D-form of polylactic acid is 1 to 9, and the number average molecular weight of this polylactic acid is suppressed to 150,000 or less (Japanese Patent Laid-Open No. 2003-11286), (C) Lactic acid-caprolactone There are only a few examples such as a copolymer (JP-A-8-92359) and (D) a compound using a dioxolane (JP-A 2003-261752).

  Therefore, it is a problem to obtain biodegradable polyester solutions having various compositions having a non-halogen solvent, especially a general-purpose non-halogen solvent, and having sufficient performance as an adhesive, pressure-sensitive adhesive, ink or coating agent.

  In the first place, the biodegradable resin dissolves when heated together with a non-halogen solvent, but forms a precipitate with subsequent cooling, and when cooled to room temperature, the whole loses fluidity or flows but precipitates. There are many cases in which a phase separation system is formed in which an object is a lower layer and a transparent liquid phase is an upper layer, that is, gelation occurs. The maximum temperature at which gelation occurs is correctly called the upper critical eutectic temperature (UCST), but is conventionally referred to herein as the gelation temperature.

  Therefore, it seems that this gelation temperature should be lowered to room temperature or below the working temperature. In consideration of the current working environment, in this specification, if the gelation temperature is 20 ° C. or lower, it is possible to work at room temperature, and a biodegradable polyester solution having a gelation temperature of 20 ° C. or lower is used as the biodegradable polyester and Obtaining from a general-purpose non-halogen solvent is an object of the present invention.

In order to solve the above problems, the present inventors have intensively studied and succeeded in obtaining a general-purpose non-halogen solvent solution of a biodegradable polyester having a gelation temperature of 20 ° C. or less. It has been found that it has excellent adhesion, adhesion and coating performance.
In addition, the gelation temperature can be obtained by actual measurement, but it has been found that a value close to the actual measurement value can be obtained by calculation, and the present invention has been completed.
That biodegradable polyester solution of the present invention is obtained by condensation of a and aliphatic dicarboxylic acids Ri weight average molecular weight of 50,000 to 800,000 der, aliphatic diols, cycloaliphatic diols, or mixtures thereof Obtained from biodegradable polyester and a general non-halogen solvent , which is a condensate or a condensate obtained by binding the condensate with a polyfunctional compound and further extending the chain, and is calculated by the following equation (1) The gelation temperature _Tm is 20 ° C. or less.

Where d _s , c and M _s are the specific gravity, volume fraction and molecular weight of the general-purpose non-halogen solvent at 20 ° C., respectively, and Δh, d _p and T _m ⁰ are the melting points of the biodegradable polyester, respectively. Heat (mJ / mg), specific gravity at 20 ° C. and melting point (° C.).

  The general-purpose non-halogen solvent is preferably a hydrocarbon, ester, ether, acetal, ketone or a mixture thereof.

  In particular, the general-purpose non-halogen solvent is preferably an acetate ester, an aromatic hydrocarbon, a ketone, or a mixture thereof.

  Further, the general-purpose non-halogen solvent is more preferably ethyl acetate, butyl acetate, toluene, xylene, methyl ethyl ketone, or a mixture thereof.

The weight average molecular weight of the biodegradable polyester, it is favorable preferable is 7 0,000～600,000. If the weight average molecular weight is less than 50,000, physical properties such as good adhesion cannot be obtained, and if it exceeds 800,000, it is difficult to dissolve in a general-purpose non-halogen solvent, which is not preferable.

  Since the present invention is configured as described above, the biodegradable polyester solution of the present invention does not gel at a temperature higher than 20 ° C., and is used as an adhesive, a pressure-sensitive adhesive, a coating agent, etc. at normal room temperature or working temperature. Work at room temperature is possible, for example, it can be applied uniformly on paper.

  In addition, since the biodegradable polyester solution of the present invention is obtained from a biodegradable polyester and a general-purpose non-halogen solvent, problems on the global environment and safety can be avoided.

  According to the present invention, biodegradable solution-type adhesives, pressure-sensitive adhesives, coating agents, etc., which are remarkably superior in adhesive strength, adhesion strength, water resistance, etc., compared to non-biodegradable and emulsion types, are biodegradable. Polyester and general-purpose non-halogen solvents can be used.

<About formula (1)>
As described below, we studied the above-mentioned problems using interaction parameters between a resin as a solute and a solvent as a solvent, and the gelation temperature T _m calculated by the following equation (1) is 20 ° C. It has been found that a solution obtained from a biodegradable polyester and a general-purpose non-halogen solvent as described below satisfies this problem.

Where d _s , c and M _s are the specific gravity, volume fraction and molecular weight of the general-purpose non-halogen solvent at 20 ° C., respectively, and Δh, d _p and T _m ⁰ are the melting points of the biodegradable polyester, respectively. Heat (mJ / mg), specific gravity at 20 ° C. and melting point (° C.).

  First, many of biodegradable polyesters are crystalline, and the fact that their melting point is lowered by the addition of a solvent or a plasticizer is represented by the following formula (2), which is a formula for lowering the melting point (freezing point).

In the formula, t _m ⁰ is the melting point of the crystalline biodegradable polyester, t _m is the melting point of the crystalline biodegradable polyester lowered by the addition of a solvent or a plasticizer (both units are absolute temperature K), and R is the gas constant. , V _p is the molecular volume of the repeating unit of the crystalline biodegradable polyester, V _s is the molecular volume of the solvent, ΔH is the heat of fusion per mole of the repeating unit of the crystalline biodegradable polyester (mJ / mg), c is The volume fraction of the solvent and μ represent the interaction parameters between the crystalline biodegradable polyester and the solvent.

This is known as Flory's formula (for example, "Mechanical properties of polymers" written by LE Nielsen, translated by Shigeharu Onoki, KK Kagaku Dojin, 1965, p. 31). In formula (2), the melting point t _m ⁰ , the heat of fusion ΔH and the molecular volume V _p are used as the crystalline biodegradable polyester-related factors, the molecular volume V _s is the solvent-related factor, and the solvent volume is used as the solution-related factor. The rate c and the interaction parameter μ between the crystalline biodegradable polyester / solvent are used, and the melting point drop of the crystalline biodegradable polyester due to the addition of a solvent or plasticizer combines these factors (2) It is shown to be determined by

  We can extend this equation (2) to a system like the present invention that has more solvents than if it is normally used, that is, a system in which the target is not a solid but a liquid (solution). I examined it. Actually, examination was made using equation (3) obtained by modifying equation (2).

In the formula, T _m (° C.) = T _m (K) -273, T _m ⁰ (° C.) = T _m ⁰ (K) -273, gas constant R = 1.986 (cal / deg / mol) × 4. 186 (J / cal) = 8.31 (J / deg / mol), Δh = ΔH / M _p (mJ / mg), V _p = M _p / d _p , V _s = M _s / d _s , d _s Is the specific gravity at 20 ° C. of the solvent, d _p is the specific gravity at 20 ° C. of the repeating unit of the biodegradable polyester, M _s is the molecular weight of the solvent, and M _p is the molecular weight of the repeating unit of the biodegradable polyester. However, t _m ⁰ was the melting point (K) of the biodegradable polyester sample itself.
This Δh can be obtained by measuring the heat of fusion.

As a result, the expression (2), that is, the expression (3) can be applied to the system of the present invention, and the melting point of the system calculated by the expression (3) can be considered as an index of the gelation temperature of the system. I found it.
First, in the formula (2), t _m ⁰ , R, V _p , c, ΔH, and V _s can be measured or measured using literature values. Therefore, μ can be considered as a function of T _m only. Therefore, an interaction parameter μ between the biodegradable polyester and the solvent necessary for using the expression (3) will be described. Since this value is not available in our research area, we decided to obtain this value from experiments. The biodegradable polyester was heated and dissolved in a solvent, allowed to gel by cooling subsequently the solution, followed by heating again the temperature for melting of the gel, i.e. the gelling temperature was measured and the value as T _m ( 3) Substituting into the equation, μ was obtained. The resulting μ is correlated with the dissolution state of the expected biodegradable polyester, good as low system of solvent system, i.e. gelling temperature T _m small, the result that the higher the system greater antisolvent system i.e. gelling temperature T _m (See Reference Examples 1 to 3).

Based on the above, it is considered possible to apply the formula (3), that is, the formula (2) to the system of the present invention, and then μ was similarly determined for the biodegradable polyester / general-purpose non-halogen solvent system. A value of about 0.9 was obtained regardless of the composition of the conductive polyester and the type of the general-purpose non-halogen solvent (see Reference Examples 4 to 9, Table 1). As a result of these studies, Equation (3), that is, Equation (1) in which μ = 0.9 is substituted, is obtained, and the satisfaction of satisfying that the gelation temperature T _m of Equation (1) is 20 ° C. or less. It has been found that the degradable polyester solution is a biodegradable polyester solution capable of working at room temperature.

In the formula, d _s , c and M _s are specific gravity, volume fraction and molecular weight of a general-purpose non-halogen solvent at 20 ° C., respectively, and Δh, d _p and T _m ⁰ are heats of fusion of the biodegradable polyester ( mJ / mg), specific gravity at 20 ° C. and melting point (° C.).

Here, further utility using the formula (1) derived in the present invention will be described. One is the ability to predict the limitations of the known technology. The above prior art will be examined. First, the biodegradable polyester that satisfies the prior art (A) in which the solubility of the biodegradable polyester is maintained by limiting the number average molecular weight to 15,000 or less is calculated by the formula (1). solution of the biodegradable it (see Comparative example 1) there is a fairly high than the gelling temperature T _m is 71.2 ° C. and room temperature of the polyester solution, also the prior art (C) i.e. the biodegradable polyester according caprolactone copolymer even in those obtained by the technique, (1) the gelation temperature T _m of a solution to be calculated in some cases much higher than 60.0 ° C. and room temperature expression (see Comparative example 2), and also In the case of the biodegradable polyester solution using the dioxolane solvent corresponding to the prior art (D), the gelation temperature T _m of the solution according to the formula (1) is 42.7 ° C., which is a little impossible to call room temperature. Arco (Comparative Reference Example 3), etc., even the above-mentioned prior art that does not lead to room temperature solution of unconditionally was suggested. Gelation temperature measured value with respect to these prior art fact, was close almost to the calculated value T _m.

  Another benefit is that a method for achieving room temperature solution was shown on the desk, and it was possible to predict whether a biodegradable polyester solution that would not gel at room temperature could be obtained. A new biodegradable polyester that achieves room temperature solution was actually synthesized (see Examples 1-3).

<Biodegradable polyester>
Examples of the biodegradable polyester referred to in the present invention include biodegradable fats obtained by condensation of aliphatic dicarboxylic acids and aliphatic diols such as polybutylene succinate, polyethylene succinate and poly [(tetrahydro) xylyl] succinate. Biodegradable aliphatic polyesters obtained by self-condensation of aliphatic hydroxycarboxylic acids such as aliphatic polyesters, polyglycolic acid, polylactic acid, polycaprolactone, and so-called co-condensed biodegradable aliphatic polyesters obtained by selecting multiple combinations thereof The biodegradable polyester obtained by condensing an aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid within a range not impairing the biodegradability, or the terminal groups of the above-described biodegradable polyester, for example, an isocyanate group or a silanol group Multiple officers with multiple Chain-extended biodegradable polyester obtained by bonding or the like based compound or carbonic acid diester, furthermore of such aforementioned biodegradable Porisuteru branched structure rather than a linear structure, (1) the T _m ≦ Those having a melting point satisfying 20 ° C., heat of fusion, and specific gravity.

<General purpose non-halogen solvent>
In the present invention, a halogen solvent that dissolves various biodegradable polyesters but adversely affects the global environment and safety, and a general-purpose non-halogen solvent without using a non-generic solvent as a solvent. It is significant that a biodegradable polyester solution was obtained using

Examples of the general-purpose non-halogen solvent referred to in the present invention include solvents that do not contain halogen and have a molecular weight and specific gravity that satisfy the formula (1). Preferably, general-purpose non-halogen solvents such as esters, hydrocarbons, ethers, acetals, ketones, more preferably acetates, aromatic hydrocarbons, ethers, ketones, etc., and even more preferably ethyl acetate (AcOEt), butyl acetate (AcOBu) ), toluene, xylene, mesitylene, diisopropyl ether ⁽ⁱ _Pr 2 O), tetrahydrofuran (THF), dioxane, anisole (pHome), acetone, such as methyl ethyl ketone (MEK), readily available, yet handling standards on safety Are generally known non-halogen solvents.

<Dissolution method>
In order to dissolve the biodegradable polyester in the general-purpose non-halogen solvent, both may be mixed, heated to the boiling point of the general-purpose non-halogen solvent, and stirred. If this required time is short, gelation may occur during the subsequent cooling to room temperature, so this point needs attention.

<Solution concentration>
The concentration (weight percentage) of the biodegradable polyester solution of the present invention is in the range of 1% to 60%, preferably 5% to 50%, more preferably 10% to 40%.

<Application>
The general-purpose non-halogen solvent solution of the biodegradable polyester of the present invention can be used as an adhesive, a pressure-sensitive adhesive, a coating agent, an ink or the like. In particular, when general objects (base materials) such as adhesion, adhesion, coating, and printing are biodegradable, conventional processed non-biodegradable adhesives can be obtained without sacrificing biodegradability. It exhibits superior performance compared to the same adhesive, the same coating agent and the same ink.

  In other words, when bonding, sticking, coating, printing, etc. based on paper, yarns, woven fabrics, knitted fabrics, nonwoven fabrics obtained from natural fibers, wood-based materials, and films, sheets, molded products obtained from aliphatic polyesters, etc. The final processed product can be obtained while maintaining the biodegradable characteristics.

  Apart from that, if the final processed product is widely dispersed in the global environment and cannot be collected and disposed of, for example, it can be applied to ships, marine structures, soil, etc. Applications include surface reinforcing processing agents, sustained release processing agents for agricultural chemicals and fertilizers.

  In addition, in order to facilitate the separation and recovery of the final processed product upon recycling after use, there is also an application utilizing the readily hydrolyzable property of the biodegradable polyester of the present invention. For example, the water-resistant paper or oil-resistant paper obtained by applying the biodegradable polyester solution of the present invention is hydrolyzed in an alkaline bath and recovered as a raw material pulp.

  The above is a feature of the biodegradable polyester solution of the present invention in comparison with a non-biodegradable resin solution. As an adhesive or coating agent, emulsions containing biodegradable polyester particles are also commercially available. Therefore, the features of the biodegradable polyester solution of the present invention against this will be briefly described. The basic difference is that the water resistance of the film obtained by transpiration of the liquid phase part of the biodegradable polyester solution of the present invention is remarkably high. Further, the denseness of the obtained film is remarkably excellent, does not contain foreign substances, and can be formed at room temperature. All of these do not require the emulsion stabilizer included as an essential component in commercially available emulsions, the biodegradable polyester solution of the present invention, and the biodegradable polyester is solvated until the solution is filmed. It comes from being. Water-resistant paper that requires strict water resistance, fertilizer that requires diffusion from pores at the molecular level and dislikes macro pores, sustained-release coating on pesticides, food packaging that requires extreme reduction of elution The advantages of the solution type, such as the biodegradable polyester solution of the present invention, can be used for processing paper, printing that requires room-temperature coating, ship bottom coating, and other adhesives that cannot be used in the emulsion type. Expected to be demonstrated. The solution type contains a solvent that is not in the emulsion type, but the collection and reuse of the transpiration of the solvent, the prevention of environmental pollution by a centralized ventilation device, and the proper use of protective equipment or thorough safety education are carried out. May be.

  In the expected use described above, the biodegradable polyester solution of the present invention can be used as it is or mixed with other components as necessary. Examples of other components include colorants, plasticizers, fillers, tackifiers, extenders, and resins. These are used by being mixed within a range that does not inhibit the original characteristic of biodegradability of the biodegradable polyester solution of the present invention.

Hereinafter, the present invention will be described in more detail with reference to examples. However, this invention is not restrained by them.
<Biodegradability test>
The biodegradability test was conducted by the soil embedding method as described below.
The test soil is set to a water content ratio of 50% of the maximum water capacity, a 10 cm square test sample is embedded in this, and the time-dependent change of the test sample at 25 ° C. is visually observed. A scale. As the test soil, the soil (which is volcanic ash ash soil) of SDS Minori Farm, Yuki Minato-cho, Higashiibaraki-gun, Ibaraki Prefecture was used. The test soil was used 400 times as much as the test sample.

<Measurement of gelation temperature>
Unless otherwise specified, the biodegradable polyester solution was subjected to differential thermal analysis (DSC), and the gelation temperature of the solution was measured and determined. Specifically, about 20 mg of the solution is collected in a DSC container, once cooled to -70 ° C, and then the temperature corresponding to the minimum point of the endothermic peak that appears when the temperature is raised at a rate of 10 ° C / min is gelled. It was temperature. It was clearly distinguishable from the endothermic peak due to the solvent.

<Measurement of weight average molecular weight and number average molecular weight>
The weight average molecular weight and number average molecular weight were determined by the GPC method using chloroform as an eluent. The conditions were as follows.

<GPC measurement conditions>
Measurement model: Shodex System-11
Column: Shodex GPC K-806M, K-802 (two each)
Eluent: Chloroform (CHCl ₃ )
Sample concentration: 0.2% by weight
Flow rate: 1.0 ml / min Injection volume: 100 μl
Temperature: 40 ° C
Detector: Shodex RI-71
Reference material: Shodex STANDARD M-75 (PMMA)

<Measurement of melting point and heat of fusion>
The melting point and heat of fusion of the biodegradable polyester were also measured by the DSC method under the same temperature conditions as described above [Measurement of gelation temperature]. The amount of the test sample was about 10 mg, the temperature corresponding to the minimum point of the endothermic peak was the melting point, and the endothermic amount per unit weight calculated from the endothermic peak area was the heat of fusion.
The specific gravity d _p was determined from the ratio of the dry weight to the weight in water using a solid specific gravity measuring device (KK Shimadzu Libor SGM-200).
The specific gravity d _s was based on literature values (Solvent Pocket Book, Ohmsha, published in 1967). However, in the case of a mixed solvent, it was calculated by assuming that there was no volume change due to mixing.
The volume fraction was calculated by assuming that there was no volume change due to mixing.

<Reference Example 1>
A biodegradable polyester Bionore 3001M (polybutylene succinate co-adipate, melting point 91.5 ° C., Showa High Polymer) was placed in a separable four-necked flask with an internal volume of 300 ml equipped with a condenser, thermometer and stirring device. KK) About 20 g and chloroform 180 g were charged, heated with a mantle heater and stirred and dissolved under reflux of chloroform. After 3 hours, it was cooled to room temperature and then taken out to obtain a transparent solution. Solid content 11.0%, the measured values of the gelation temperature The _{T m} was -40 ° C.. (3) T _m = −40 ° C., T _m ⁰ = 91.5 ° C., Δh = 37.6 mJ / mg, d _p = 1.23, d _s = 1.15, M _s = 119, and c = 0.870 was substituted to obtain μ = −0.030. Chloroform is known as a good solvent for biodegradable polyester, and this value of μ = −0.030 was in line with expectations.

<Reference Example 2>
The experiment was conducted in the same manner as in Reference Example 1 except that the solvent was toluene and the biodegradable polyester was polycaprolactone (Cell Green PH4, melting point 63.7 ° C., Daicel Chemical Industries K.K.). 1%, to obtain a measured value = 6.7 ° C. comprising a solution of the gelling temperature _{T m.} d _s = 0.867, M _s = 92.1, c = 0.922, T _m = 6.7 ° C., T _m ⁰ = 63.7 ° C., d _p = 1.14 and Δh = 73.1 mJ / By substituting mg into the equation (3), a value of μ = 0.325 was obtained.

<Reference Example 3>
Experiments were conducted in the same manner as in Reference Example 1 except that the solvent was toluene, and a solution having a solid content concentration of 11.9% and an actual measurement value of gelation temperature T _m = 65.9 ° C. was obtained. Substituting the same values as in Reference Example 1 into equation (3) except for d _s = 0.867, M _s = 92.1, c = 0.912, and T _m = 65.9 ° C., μ = 0.948 is set. Obtained.

  The value of μ obtained from Reference Examples 1 to 3 is large in order of the actual gelation temperature of the biodegradable polyester solutions of Reference Examples 1 to 3, that is, the magnitude consistent with the expectation that the value increases as the solvent becomes poorer. It was a relationship.

<Reference Examples 4 to 9>
Except for changing the combination of the biodegradable polyester and the general-purpose non-halogen solvent as shown in Table 1, the experiment was conducted in the same manner as in Reference Example 1, and μ was obtained from the equation (3). These are collectively shown in Table 1.

  As shown in Table 1, μ of the biodegradable polyester solution composed of a combination of four commercially available biodegradable polyesters and five general-purpose non-halogen solvents is about 0 from the same experiment as in Reference Example 1. .9.

<Example 1>
Charged 230.3 g of dodecanedioic acid and 123.9 g of 3-methyl-1,5-pentanediol in a 500 ml separable round bottom four-necked flask equipped with a stirrer, thermometer, fractionation pipe and gas inlet pipe. The mixture was heated to 200-210 ° C. with a mantle heater and dehydrated and condensed. The acid value of the product after 14.5 hours was 9.9 (mg KOH / g sample). Cool to 100 ° C under nitrogen flow, add 0.177 g of titanium tetraisopropoxide to this, change the fractionating tube to a DC tube, heat to 200-210 ° C while reducing the pressure with a vacuum pump, and deglycolize Reaction was performed. The degree of vacuum finally reached 0.5 torr. A slightly yellow melt with a very high viscosity was obtained. Next, it is cooled to 180 ° C., returned to normal pressure under a nitrogen gas flow, 0.08 g of phosphorous acid is added and stirred, 3 g of hexamethylene diisocyanate is added, and chain extension reaction is carried out at the same temperature. went. The obtained product was a faint yellow, viscous and soft biodegradable polyester having a weight average molecular weight of 213,451, a melting point of −3 ° C., and a heat of fusion of 37.8 mJ / mg.

Next, 80 g of the product is weighed into a 500 ml separable flask equipped with a stirrer, a condenser and a thermometer, and 180 g of general-purpose non-halogen solvent, n-butyl acetate, is added and dissolved by heating for 3 hours under reflux. After cooling, it was cooled. A slightly yellow liquid with a solid content of 30.1% was obtained. The gelation temperature T _m according to the equation (1) of this solution was calculated to be −24.9 ° C. However, T _m ⁰ = −3 ° C., Δh = 37.8 mJ / mg, d _p = 1.22, d _s = 0.882, M _s = 116 and c = 0.663. Found gelation temperature the T _m was -30.5 ° C., was close to the calculated value. Thus, it was found that the accuracy of the expression (1) is high.

<Example 2>
Using 115 g of succinic acid, 94.9 g of adipic acid, 120 g of 1,4-butanediol, and 22.2 g of ethylene glycol, the final vacuum degree in the deglycolization reaction was 0.05 torr, and the final chain extension reaction temperature was 160 ° C. Except that, a slightly cloudy biodegradable polyester having a weight average molecular weight of 120,585, a melting point of 47.5 ° C., and a heat of fusion of 19.5 mJ / mg was obtained in the same manner as in Example 1.

A slightly turbid solution having a solid content of 21.0% was obtained in the same manner as in Example 1 except that the biodegradable polyester was used and 300 g of ethyl acetate was used as a general-purpose non-halogen solvent. Gelling temperature _{T m} by (1) the slightly cloudy solution was calculated to -13.4 ° C.. However, T _m ⁰ = 47.5 ° C., Δh = 19.5 mJ / mg, d _p = 1.23, d _s = 0.902, M _s = 88.1 and c = 0.837. Found gelation temperature The T _m is -9.9 ° C., it was close to the calculated value. Thus, it was found that the accuracy of the expression (1) is high.

<Example 3>
The same apparatus as in Example 1 was charged with 63.0 g of succinic acid, 77.9 g of adipic acid, 149.2 g of cyclohexyldimethanol, and 99.6 mg of germanium oxide as a catalyst, and subjected to dehydration condensation at 180 ° C. for 40 minutes. Next, the distillation tube was replaced with a direct current tube, and the reaction was carried out at 180 ° C. under a reduced pressure of 20 torr for 1.8 hours, and finally the reaction was carried out at 220 ° C. and reduced to 0.1 torr for 13.6 hours. The product was a clear, colorless and viscous melt. The product was analyzed after cooling to obtain a biodegradable polyester having a weight average molecular weight of 86,253, a melting point of 63.8 ° C., and a heat of fusion of 23.2 mJ / mg.

  A colorless and transparent solution having a solid content of 14.0% was obtained in the same manner as in Example 1 except that 30 g of the biodegradable polyester and 270 g of an equal weight mixture of toluene / methyl ethyl ketone (MEK) as a general-purpose non-halogen solvent were used.

Gelling temperature _{T m} by equation (1) of the clear colorless solution was calculated to 15.0 ° C.. However, T _m ⁰ = 63.8 ° C., Δh = 23.3 mJ / mg, d _p = 1.23, d _s = 0.835, M _s = 82.1 and c = 0.900. This colorless and transparent solution was placed in a cylindrical glass bottle having an internal volume of 140 ml, and this was placed in a forced circulation thermostat at 10 ° C. One week later, the result of visual observation of the colorless and transparent solution did not change, and the measurement result of the viscosity of the colorless and transparent solution by a rotational viscometer did not change to 20 ± 1 mPa · s, and the actual measurement value of the gelation temperature T _m was It became less than 10 degreeC.

<Application Example 1: Application to adhesives>
The biodegradable polyester solution of Example 1 was applied to a film (30 μm thick) obtained from Bionore # 1001 (polybutylene succinate, Showa High Polymer KK), a biodegradable polyester, with a 2 mil applicator. After application and air drying, the film was further heat-treated for 1 minute with a hot air circulating dryer at 100 ° C. to prepare an adhesive film. Biodegradation of Example 1 as a result of ball tack 3, adhesive strength 1.5N / 25mm (to glass), 2.0N / 25mm (to stainless steel plate), holding time 4.5 hours, no adhesive residue after peeling. It was shown that the conductive polyester solution can be used as a re-peelable pressure-sensitive adhesive. The measurement below the ball tack was in accordance with JIS Z 0237. In a biodegradation test by embedding the adhesive film in soil, the adhesive film did not retain its original shape after 6 months.

<Application Example 2: Application to Printing Ink>
100 g of the biodegradable polyester solution obtained in Example 2, 6 g of carbon black, 0.6 g of a surfactant (decaglyceryl trioleate) and 150 g of glass beads are placed in a 500 ml flask, and a disper (TK auto homomixer, special machine chemical) KK) was inserted and stirred at 2000 rpm for 1 hour, and finally 1 g of aliphatic isocyanate (Coronate L, Nippon Polyurethane KK) was added to obtain a black ink. Using this, a color image (halftone dot pattern) is screened on a biodegradable polyester Bionore # 3001 (polybutylene succinate co-adipate, Showa High Polymer KK) film (50 μm thick). Printing was performed by a printing method to fix the image. One week later, when the cellophane (registered trademark) was adhered to the printed surface and then peeled off, the image was not damaged. A test in which the printed piece was immersed in 20 ° C. water for 10 minutes did not damage the image, indicating that the printed surface had sufficient water resistance. In the biodegradability test of this printed matter by the soil burying method, the original form was not recognized after 6 months.

<Application Example 3: Application to draining bags>
A biodegradable rayon nonwoven fabric (weighing 26.7 g / m ² , 4 pieces of 10 cm square) is immersed in 200 g of the biodegradable polyester solution obtained in Example 3, taken out after 2 minutes, and squeezed and air-dried with a rubber roller. did. Two sheets of the obtained biodegradable polyester solution-impregnated non-woven fabric were stacked, heat sealed using an iron at 100 ° C./0.3 Mpa / 10 s, and subjected to a strength test. The strength in the 180 ° peel test (sample size: 2.5 cm width, chuck interval 8 cm, peel speed 300 mm / min) is 0.55 kg / cm in a normal state (20 ° C., 65% RH) and wet (at 20 ° C. After immersing in water for 1 hour, the surface water was wiped with filter paper and measured at 20 ° C. and 65% RH)), 0.53 kg / cm, which was sufficient for draining bags. In addition, one piece of the heat-sealed product was subjected to a recycling test. This sample is cut into approximately 2cm squares, immersed in 70g of 5N caustic soda solution at room temperature all day and night, then poured into a household juice mixer with 500ml of water and stirred. After 5 minutes, it is disaggregated into a single fiber and recycled. It was shown to be suitable. In addition, the heat-sealed product did not retain its original shape after 7 months in a biodegradability test by embedding soil.

<Comparative Example 1>
Bionore polyester Bionon 3050M (polybutylene succinate co-adipate, melting point 94.9 ° C., heat of fusion Δh = 52.2 mJ / mg, Showa High Polymer KK), 60 ° C., 90% RH Hydrolysis was carried out under the above conditions for 20 days to give a weight average molecular weight of 17,700 (number average molecular weight of 9,600). When the gelation temperature T _m of a toluene solution having a solid content concentration of 10% using this was calculated by the equation (1), it was 71.2 ° C., which was a slightly high temperature for solubilization at room temperature. Gelling temperature T _m was measured in accordance with Reference Example 3 was close to the calculated value and 64.6 ° C.. Thus, it was found that the accuracy of the expression (1) is high. However, T _m ⁰ = 94.9 ° C., Δh = 52.2 mJ / mg, d _p = 1.23, d _s = 0.867, M _s = 92.1 and c = 0.927 are used for the calculation. It was.

<Comparative Example 2>
A copolymer obtained from ε-caprolactone and lactic acid (melting point = 174.3 ° C.) falls within the range of the prior art (C) in which a copolymer of ε-caprolactone and lactic acid is soluble in a general-purpose solvent at room temperature. , heat of fusion = 10.9mJ / mg, the weight average molecular weight 538,000, K.K. the BMG), the gelation temperature _{T m} of a when dissolved in toluene so that the solid content concentration of 5.0% ( As calculated by the formula (1), the temperature was 60.0 ° C., which was a little higher for room temperature solubilization. The gelation temperature measured according to Reference Example 2 was 53.1 ° C., which was close to the calculated value. Thus, it was found that the accuracy of the expression (1) is high. However, T _m ⁰ = 174.3 ° C., Δh = 10.9 mJ / mg, d _p = 1.20, d _s = 0.867, M _s = 92.1 and c = 0.963 are used for the calculation. It was.

<Comparative Example 3>
In accordance with the above-mentioned prior art (D) that the biodegradable polyester is dissolved in a specific 1,3-dioxolane compound at room temperature, gelation when Bionore 3001M, a biodegradable polyester, is used as a 10% solid content solution. the temperature _{T m,} was calculated by the equation (1). The value was 42.7 ° C., which was higher than room temperature. The actual measurement value according to Reference Example 3 was 40.6 ° C., a value close to the calculation result. Thus, it was found that the accuracy of the expression (1) is high. However, T _m ⁰ = 91.5 ° C., Δh = 37.6 mJ / mg, d _p = 1.23, d _s = 1.07, M _s = 74.1 and c = 0.912 are used for the calculation. It was.

<Comparative example 4>
Resin solution in which EM-301 (polybutylene succinate co-adipate system, solid content 51%, minimum film formation temperature 95 ° C., Showa High Polymer KK), a biodegradable polyester emulsion, is diluted to 10%. An experiment was conducted in the same manner as in Application Example 3 except that. The 180 ° peel strength of the obtained heat-sealed product is 0.25 kg / cm in a normal state and 0.0 kg / cm when wet (however, 0.20 kg / cm when the sample is immersed in water for 10 minutes). The result was insufficient for draining bags.

As can be seen from the above, it was found that the gelation temperature can be predicted with high accuracy by the equation (1) of the present invention. In the examples, the gelation temperature T _m of the biodegradable polyester solution of the present invention is calculated and predicted to be 20 ° C. or less by the equation (1), and a value close to the calculated value is obtained even in actual measurement. It was below ℃. These biodegradable polyester solutions of the present invention also showed excellent performance when applied to several applications. Also in the biodegradation test, the biodegradable polyester solution of the present invention showed good biodegradability.

On the other hand, in the comparative example, the gelation temperature _Tm was calculated and predicted to be higher than 20 ° C. according to the equation (1), and a value close to the calculated value was obtained even in actual measurement, and was higher than 20 ° C. Application of the comparative example did not give excellent performance.

Claims (5)

And weight-average molecular weight and the aliphatic dicarboxylic acids Ri der 50,000 to 800,000, aliphatic diols, or condensation products obtained by condensation of cycloaliphatic diol or a mixture thereof, or the condensate of is bound by polyfunctional compounds obtained from the biodegradable polyester and a general non-halogen solvent condensation products obtained by further chain extension, the following (1) gelling temperature T _m calculated by the equation 20 ° C. or less A biodegradable polyester solution.

(Where d _s , c and M _s are the specific gravity, volume fraction and molecular weight of the general-purpose non-halogen solvent at 20 ° C., respectively, and Δh, d _p and T _m ⁰ are the heat of fusion of the biodegradable polyester, respectively. (MJ / mg), specific gravity at 20 ° C. and melting point (° C.)) The biodegradable polyester solution according to claim 1, wherein the general-purpose non-halogen solvent is a hydrocarbon, an ester, an ether, an acetal, a ketone, or a mixture thereof. The biodegradable polyester solution according to claim 1, wherein the general-purpose non-halogen solvent is an acetate ester, an aromatic hydrocarbon, a ketone, or a mixture thereof. The biodegradable polyester solution according to claim 1, wherein the general-purpose non-halogen solvent is ethyl acetate, butyl acetate, toluene, xylene, methyl ethyl ketone, or a mixture thereof. The biodegradable polyester solution according to claim 1, wherein the biodegradable polyester has a weight average molecular weight of 70,000 to 600,000.