JPH0931179A - Lactic acid base polyether copolymer resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable lactic acid base polyether copolymer resin composition having sufficient thermal stability and having rigidity, flexibility and transparency different according to uses. SOLUTION: This composition with a weight-average molecular weight of 1,000 to 150,000 has repeating units comprising polylactic acid segments of a weight-average molecular weight of 70 to 100,000 obtained by copolymerizing lactide and a poly(oxyethylene-oxypropylene) polyol in the presence of a polymerization catalyst, polyethylene oxide segments of a weight-average molecular weight of 100 to 20,000 and polypropylene oxide segments of a weight-average molecular weight of 100 to 20,000, with the terminal comprising the polylactic acid segments.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is useful for molding resins such as sheet / film materials, coating resins, ink resins, medical material resins, adhesive resins, paper lamination resins, foaming resin materials and the like. The present invention relates to a lactic acid-based polyether copolymer resin composition capable of various molding processes, a method for producing the same, and a molded article formed from the resin composition.

The lactic acid type polyether copolymer resin according to the present invention has biodegradability and transparency and can be molded by various methods such as extrusion molding, injection molding, blow molding and press molding. It is possible to mold using the existing equipment used for general-purpose resin, molding resin,
It is useful for paint resin, ink resin, adhesive resin, etc.
It is particularly useful as a resin for molding packaging materials.

For example, as a processed product of an extruded sheet,
For trays, cups, lids, blister, etc., as film processed products, for wrap packaging, shrink packaging, stretch packaging, etc., as well as bags such as garbage bags, plastic bags, general standard bags, heavy bags, etc. It can be used advantageously. Other agricultural and fishery materials used for extruded products include agricultural mulch film, agricultural chemical sustained-release sheets, bird-prevention nets, curing sheets, seedling pots, fishing nets, seaweed cultivation nets, fishing lines, and sanitary diapers. Sanitary ware, artificial kidney for medical use,
Examples include sutures. Examples of blow-molded products include shampoo bottles, cosmetic bottles, beverage bottles, oil containers and the like. As a laminate with paper, it is used for trays, one-way containers such as cups, and megaphones.

Injection-molded products include golf tees,
It can be applied to cotton swab cores, candy sticks, brushes, toothbrushes, syringes, lids, plates, cups, combs, razor handles, tape cassettes, disposable spoons / forks, stationery such as ballpoint pens. Others, binding tape, prepaid card, balloons, pantyhose, hair cap, sponge, cellophane tape, umbrella, duck, plastic gloves,
Examples include various applications such as hair caps, ropes, tubes, foam trays, foam cushioning materials, cushioning materials, packing materials, hot melt adhesives, cigarette filters, and ship bottom paints.

[0005]

2. Description of the Related Art In recent years, due to environmental problems and the like, much research has been conducted to widely utilize lactic acid-based polymers having excellent biodegradability as general-purpose polymers, and many studies and patent applications relating to the production method have been made. ing. However, it is difficult to say that conventionally known polylactic acid, which is a polymer of lactic acid or lactide, or a copolymer of lactic acid and another monomer has sufficiently satisfactory performance in moldability, transparency, and heat resistance. However, except for special uses, there is a problem in using it as a general-purpose resin, and improvement of these polylactic acid-based polymers is desired.

JP-A-1-108226 describes a block copolymer comprising a polylactic acid segment and a polypropylene glycol segment, a method for producing the block copolymer, a copolymer film and a copolymer fiber. However, if the polypropylene glycol segment exceeds 30% by weight in the copolymer, it becomes difficult to form a film or a fiber.

Further, Japanese Patent Laid-Open No. 3-45265 discloses that
A copolymer of polylactic acid and polyethylene glycol is described as a medical composition. However, in this manufacturing method, after polylactic acid is first polymerized and then reacted with polyethylene glycol, it is necessary to soften or melt the polylactic acid. A method is also known in which after polylactic acid is polymerized, polyethylene glycol is added to carry out polymerization.

However, in both methods, the polymerization time is longer, the thermal history is increased, and coloring is more likely to occur, as compared with the method of manufacturing from lactide and polyethylene glycol. In addition, the reaction time is longer due to the smaller number of reactive end groups.
In addition, the polymerization process is performed twice, which is not a simple production method. In addition, the copolymers obtained by these methods are in the form of semi-wax, and it is not possible to obtain molded products such as films and sheets, which is one of the fields of application of the present invention.

Further, Japanese Patent Publication No. 6-508831 discloses a nanoparticle composed of a block copolymer of polyoxyethylene and polylactic acid. This invention is intended for medical use. The lactic acid-based polymer portion is a polymer containing 50:50 D and L isomers of lactic acid, and the resulting copolymer is an amorphous polymer having almost no glass transition point. Heat resistance suitable for industrial use has not been obtained.
Therefore, it was not suitable as a resin material such as a general-purpose molded product, which is a field of application of the present invention.

Summarizing these conventional techniques, if sufficient strength, heat resistance and heat stability are provided, they are brittle and lack flexibility, and if sufficient flexibility and transparency are provided, strength, Due to poor heat resistance and thermal stability, a polymer having sufficiently satisfactory properties for use as a material resin for films and sheets has not yet been obtained.

As a means for improving these physical properties, plasticization of the polymer with an additive is considered. However, the improvement of physical properties by these plasticizing methods is, for example, when lactide, which is a residual monomer, is used as a plasticizer as a plasticizing means, the lactide sublimates and scatters to adhere to the equipment during the manufacturing process. There are problems such as the loss of the plasticizing effect due to leakage and disappearance of the plasticizer lactide from the polymer during storage or use of the product, and contamination of the packaging contents.

Also, when a known and commonly used plasticizer for polymers is added, a large amount of plasticizer needs to be added for plasticization, and the problem of bleeding out of the plasticizer is unavoidable, and plasticization during storage is required. Problems such as disappearance of effects and contamination of package contents have not been solved, and lactic acid-based polymers having sufficiently satisfactory properties have not been obtained as polymers for molded articles or packaging materials.

[0013]

SUMMARY OF THE INVENTION Therefore, the problem to be solved by the present invention is to provide a biodegradable lactic acid-based polymer having sufficient thermal stability and having rigidity, flexibility and transparency depending on the intended use. An object of the present invention is to provide an ether copolymer resin composition, a method for producing the same, and a molded article comprising the lactic acid-based polyether copolymer resin composition.

[0014]

In order to solve such a problem, the inventors of the present invention have earnestly studied and found that the weight average molecular weight is 70%.
100 to 100,000 polylactic acid segment (A), 100 to 20,000 weight average molecular weight polyethylene oxide segment (B), and 100 to 2 weight average molecular weight
A weight average molecular weight of 1,000 having a repeating unit consisting of 30,000 polypropylene oxide segments (C) and having a polylactic acid segment (A) at the end.
~ 150,000 lactic acid-based polyether copolymer resin composition does not decompose into monomers during molding, has a wide range of molding temperature, has high strength and thermal stability during molding,

When copolymerizing with lactide,
By changing the proportion and type of the polyether polyol, a toughness that does not easily break and is excellent in tear strength when processed into a film from a hard resin having a high molecular weight and a high glass transition point and a melting point. Being able to produce various lactic acid-based copolymers up to resins with highly flexible properties,

That is, a decomposable high-molecular-weight lactic acid-based polyether copolymer having sufficient strength that can be used as a general-purpose resin, thermal stability during molding, and rigidity, transparency, and flexibility depending on the application. The present invention was completed by finding that a polymer can be produced.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the present invention relates to a polylactic acid segment (A) having a weight average molecular weight of 70 to 100,000,
Polyethylene oxide segment (B) having a weight average molecular weight of 100 to 20,000, and a weight average molecular weight of 100 to
It has a repeating unit consisting of 20,000 polypropylene oxide segments (C) and has a polylactic acid segment (A) at the end, and a weight average molecular weight of 1,000 to 1
It is a 50,000 lactic acid-based polyether copolymer resin composition.

More specifically, the lactic acid-based polyether copolymer resin composition of the present invention comprises a repeating unit consisting of a polylactic acid segment (A), a polyethylene oxide segment (B) and a polypropylene oxide segment (C). (-B-C-) _n- A, (where n = 1-20
0), the polylactic acid segment (A) and the polyethylene oxide segment (B) or the polypropylene oxide (C) are linked by an ester bond, and the polyethylene oxide segment (B) and the polypropylene oxide segment (C) are an ether bond. Which are combined with

A repeating unit consisting of a polylactic acid segment (A), a polyethylene oxide segment (B) and a polypropylene oxide segment (C) is A
(-B-C-B-) _n- A, (where n = 1 to 130)
And the polylactic acid segment (A) and the polyethylene oxide segment (B) are bound by an ester bond,
One in which the polyethylene oxide segment (B) and the polypropylene oxide segment (C) are linked by an ether bond,

A repeating unit comprising a polylactic acid segment (A), a polyethylene oxide segment (B) and a polypropylene oxide segment (C) is
(-C-B-C-) _n- A, (where n = 1 to 130)
And the polylactic acid segment (A) and the polypropylene oxide segment (C) are bound by an ester bond, and the polyethylene oxide segment (B) and the polypropylene oxide segment (C) are bound by an ether bond. Which is a lactic acid-based polyether copolymer resin composition.

Further, in the present invention, the weight ratio of lactide (D) and poly (oxyethylene-oxypropylene) polyol (E) (D) / (E) = 50/50 to 97.
/ 3, the method is a method for producing a lactic acid-based polyether copolymer resin composition, which comprises copolymerizing in the presence of a polymerization catalyst.

The poly (oxyethylene-oxypropylene) polyol (E) used in the production method of the present invention is a repeating unit (-B-C-) _n consisting of a polyethylene oxide segment (B) and a polypropylene oxide segment (C). , (Where n = 1 to 200),
A repeating unit (-B-C-B-) _n consisting of a polyol having a weight average molecular weight of 200 to 40,000 or a polyethylene oxide segment (B) and a polypropylene oxide segment (C) (where n = 1 to 130).
A polyol having a weight average molecular weight of 300 to 40,000,

Alternatively, a polyethylene oxide segment (B) and a polypropylene oxide segment (C)
A repeating unit (-C-B-C-) _n (where n
= 1 to 130), including a weight average molecular weight of 300 to 40,
000 polyols. The present invention also includes a molded product made of the lactic acid-based polyether copolymer resin composition of the present invention.

Hereinafter, the present invention will be described in detail. The weight average molecular weight of the lactic acid-based polyether copolymer resin composition of the present invention is 1,000 to 150,000. Since a resin having a high molecular weight has higher strength,
For use as a molding resin for sheets, injection-molded products, etc., the molecular weight is preferably 10,000-150,000.

The polylactic acid segment (A) of the lactic acid type polyether copolymer of the present invention has a weight average molecular weight of 70 to 10.
It is about 10,000, preferably 1,000 to 10
It is 0000. The amount of the polylactic acid segment (A) in the lactic acid-based polyether copolymer is 50 to 97% by weight.
Is 60 to 90% by weight from the viewpoint of strength and biodegradability.
It is preferred that

The polyethylene oxide segment (B) and the polypropylene oxide segment (C) have a weight average molecular weight of 100 to 20,000, preferably 500 to 20,000. The weight ratio of the polyethylene oxide segment (B) to the polypropylene oxide segment (C) in the lactic acid-based polyether copolymer of the present invention is 10/90 to 90/10, preferably 30/70 to 70/30. Is.

The poly (oxyethylene-oxypropylene) polyol (E) used in the production of the lactic acid-based polyether copolymer resin composition of the present invention comprises a polyethylene oxide segment (B) and a polypropylene oxide segment (C). ), The repeating unit of the polyethylene oxide segment (B) and the polypropylene oxide segment (C) is (-B-C-) _n , (where n = 1 to 1).
200), or (-B-C-B-) _n , (where n
= 1 to 130), or (-C-B-C-) _n , (where n = 1 to 130). But,
From the viewpoint of biodegradability and thermophysical properties, those represented by Chemical Formulas 1 to 4 are particularly preferable.

[0028]

Embedded image (In the formula, m = 3 to 450, n = 2 to 340)

[0029]

Embedded image (In the formula, m = 3 to 400)

[0030]

Embedded image (In the formula, m = 3 to 330, n = 2 to 220)

[0031]

Embedded image (In the formula, m = 3 to 330, n = 2 to 220)

The poly (oxyethylene-oxypropylene) polyol (E) has a weight average molecular weight of 200 to 40,000, and a weight average molecular weight of 1,000 to 20 from the viewpoint of biodegradability. More preferably, it is about 1,000.

The amount of poly (oxyethylene-oxypropylene) polyol in the lactic acid-based polyether copolymer is 3/97 to 50/50, which is 10/90 to 40 / in terms of flexibility and strength. It is more preferably 60.

The lactic acid type polyether copolymer of the present invention is
The composition of the polylactic acid segment (A), the polyethylene oxide segment (B) and the polypropylene oxide segment (C) is A (-B-C-) _n- A, (where n
= 1 to 200), or A (-B-C-B-) _n-
A, (where n = 1 to 130), or A (-CB)
-C-) _n -A, (where n = 1 to 130), and the lactic acid-based polyether copolymer resin composition of the present invention essentially comprises at least one of these copolymers. It is a constituent component.

The lactide used in the production method of the present invention is a compound obtained by cyclic esterification of lactic acid between two molecules and is a monomer having a stereoisomer. That is, lactide includes L-lactide composed of two L-lactic acids, D-lactide composed of D-lactic acid, and MESO-lactide composed of L-lactic acid and D-lactic acid.

A copolymer containing only L-lactide or D-lactide is crystallized to obtain a high melting point. In the lactic acid-based polyether copolymer of the present invention and the method for producing the same, these three lactides are used. By combining them, preferable resin properties can be realized according to the application.

In the present invention, since high thermophysical properties are expressed, the lactide used is L-lactide in the total lactide,
The content of 75% or more is preferable, and in order to exhibit higher thermophysical properties, the lactide preferably contains L-lactide in an amount of 90% or more of the total lactide.

When the high-molecular-weight lactic acid-based polyether copolymer resin composition obtained by the present invention is formed into a sheet, a sheet having high strength to a flexible sheet can be obtained. Specifically, the tensile viscoelasticity is 500 to 50,0.
A sheet of 00 kg / cm ² is obtained.

The obtained lactic acid-based copolymer can be further increased in molecular weight by reacting with one or more compounds selected from the group consisting of oxycarboxylic acids and lactones. Specific examples thereof include citric acid, tartaric acid and malic acid as oxycarboxylic acids, and β-butyrolactone, ε-caprolactone, γ-valerolactone, γ-undecalactone and the like as lactones. Can be mentioned. When the amount of lactone increases, the glass transition point and melting point decrease, and the flexibility increases.

In order to further react these compounds with the lactic acid-based copolymer, the lactic acid-based copolymer is mixed in the reaction product after the polymerization reaction of the lactic acid-based copolymer is completed, and the mixture is stirred and mixed in a molten state for a short time, or Alternatively, the lactic acid-based copolymer obtained by polymerization may be added again and melt-mixed. Further, both the lactic acid-based copolymer and these compounds are dissolved in a common solvent,
After heating and reacting, it may be obtained by reprecipitation or degassing. Particularly preferred for oxycarboxylic acids and lactones is a method in which these are added to the obtained lactic acid-based copolymer, melt-mixed, and then reacted under reduced pressure, whereby the reaction time is shortened.

The temperature for mixing and reacting is generally 60.degree.
It is 240 ° C, preferably 80 ° C to 190 ° C. Further, in the reaction, an ester polymerization catalyst such as N, N-dimethylaniline, tin octanoate, isopropyl titanate or the like can be used. The degree of vacuum during the reaction is 100T.
Orr or less, preferably 10 Torr or less, more preferably 3 Torr or less.

The amount of oxycarboxylic acids or lactones used is preferably 0.001% by weight to 5% by weight, more preferably 0.001% by weight to 0.1% by weight, based on the lactic acid copolymer. This method is also preferable in that the used oxycarboxylic acids and lactones are bonded to the terminal groups of the lactic acid-based copolymer to form a so-called end cap, and the decomposition of the polymer into monomers by heat can be prevented.

It is desirable to use a polymerization catalyst for the production of the present invention. Examples of the catalyst used in the present invention include metals such as tin, zinc, lead, titanium, bismuth, zirconium, and germanium, which are generally known as polymerization catalysts for cyclic esters and transesterification catalysts, and derivatives thereof. For these derivatives, especially metal organic compounds,
Carbonates, oxides and halides are preferred. Specifically, tin octoate, tin chloride, zinc chloride, zinc acetate, lead oxide, lead carbonate, titanium chloride, alkoxy titanium, germanium oxide, and zirconium oxide are suitable.

The amount of the polymerization catalyst used is preferably 0.005 to 0.2% by weight based on the total amount of the polymerization components excluding the solvent.
In order to have a sufficiently high polymerization rate and to reduce the coloring of the obtained lactic acid-based polyether polyol, it is particularly preferable that
It is preferably from 0.1 to 0.1% by weight.

Next, a specific manufacturing method of the present invention will be described. In the reaction in which lactide and poly (oxyethylene-oxypropylene) polyol are mixed and polymerized, the mixture is heated and melted, or the reaction product is diluted and mixed with a solvent, and then a polymerization catalyst is added.

The polymerization temperature in the solvent-free system is preferably a temperature above the melting point of lactide and below 190 ° C. in terms of the equilibrium of the polymerization, and it is possible to prevent the lactide type polyether polyester from being colored due to the decomposition reaction. The melting point of lactide is around 100 ° C., and a temperature of 100 ° C. or higher and 190 ° C. or lower, more preferably 140 to 180 ° C. is desirable in terms of polymerization equilibrium, and a decrease in the molecular weight or coloring of the lactic acid-based polyether polyol accompanying the decomposition reaction Can be prevented.

In order to prevent decomposition and coloring of lactide,
All reactions are preferably carried out under a dry, inert gas atmosphere. Particularly, it is performed in a nitrogen or argon gas atmosphere or in a bubbling state. At the same time, it is preferable to remove water from the polyether polyols, which are raw materials, by drying under reduced pressure. Further, by using an antioxidant such as a phosphite-based compound or a phenol-based compound, it is possible to prevent a decrease in the molecular weight and coloration of the copolymer obtained.

Since lactide can be dissolved in a solvent,
Polymerization can be performed using a solvent, and specific examples of the solvent include benzene, toluene, ethylbenzene, xylene,
Examples thereof include cyclohexanone, methyl ethyl ketone, isopropyl ether and the like. Also dry these solvents,
It is preferable to remove water to obtain a copolymer having a higher molecular weight.

The high-molecular-weight lactic acid-based copolymer of the present invention can also be manufactured in a batch using an ordinary polymerization kettle. Further, the continuous manufacturing method can improve the product quality, yield and productivity.

As a continuous production method, two or more, preferably three or more agitated reactors connected in series, and / or a static mixer, and / or a horizontal reaction are used in all or part of the reaction steps. Equipment and / or vertical reactors are used.

As the agitating reactor having two or more units connected in series, the stirring method can be changed as the reaction progresses, and efficient stirring and temperature control can be performed. The use of a bath is preferred.

The static mixer is a static mixer having no moving parts, that is, a static mixer having no stirrer as compared with a mixer having a stirrer. Specifically, the static mixer is a movable part fixed in a pipe. A mixing device that mixes a solution by dividing a flow and changing or reversing the flow direction by means of a mixing element that does not exist, and repeating division, conversion, and reversal of the flow in the vertical direction and the horizontal direction.

The horizontal reactor referred to here is not only an extruder such as a single-screw or twin-screw extruder used for reactive processing, but also a twin-screw reactor capable of a long time such as a residence time of 1 hour or more. Say that.
The vertical reactor referred to here is a stirring reactor having a mechanism for supplying raw materials from below and taking out products from above with few short paths.

In these continuous production methods, polymerization can be carried out using a solvent or the like. As a result, the obtained high-molecular-weight lactic acid-based copolymer has a high melting point and a high melt viscosity, which makes it difficult to polymerize, but the addition of a solvent lowers the viscosity of the polymerization system, facilitates stirring, and facilitates polymerization. It will be easier to do.

Particularly when a continuous polymerization apparatus equipped with a static mixer is used, the extrusion pressure of the polymerization solution is lowered, and the polymerization apparatus has an internal device for a heat medium for the purpose of temperature control and a baffle plate for the purpose of stirring. Is effective because the equipment can be lightened. Since the stirring is easy, the temperature can be easily controlled, the temperature is uniform in the polymerization apparatus, and a high-molecular-weight lactic acid-based copolymer with less coloring is obtained.

Further, it is desirable to carry out devolatilization under reduced pressure for the purpose of removing lactide, solvent and odorous substances remaining in the latter stage of polymerization. By this devolatilization step, the amount of residual lactide can be reduced, and the storage stability of the obtained high molecular weight lactic acid-based copolymer can be significantly increased.

Residual lactide is not preferable because it causes hydrolysis due to adhesion of moisture or fusion due to heat when a lactic acid type polyether copolymer is used as a sheet / film. In addition, it is not preferable because it is scattered by sublimation from the film or sheet that is commercialized. Therefore, the amount of residual lactide in the lactic acid-based copolymer of the present invention is preferably 2% by weight or less. More preferably, it is 1% by weight or less.

As a concrete devolatilization method, a single-screw or twin-screw extruder, a thin-film distilling machine, a pot type depressurizing device and the like are used. As a devolatilization condition, a method of taking out while heating under reduced pressure after polymerization is preferable. In order not to reduce the molecular weight of the lactic acid-based copolymer, devolatilization conditions are as follows: devolatilization time: 5 seconds to 10 minutes, temperature: 100 to 230 ° C., decompression degree: 0.1.
It is preferable to carry out at 600 Torr.

As another devolatilization method, there is a method in which after the completion of the polymerization, the lactic acid-based copolymer is pelletized or pulverized and taken out under reduced pressure while heating. Also in this case, for the purpose of not reducing the molecular weight of the lactic acid-based copolymer, the devolatilization time is preferably 2 to 400 minutes, the temperature is 60 to 200 ° C., and the degree of vacuum is preferably 0.1 to 50 Torr.

The production method according to the present invention can provide high-molecular-weight lactic acid-based polyester having high rigidity to high-molecular-weight lactic acid-based polyester having high flexibility. That is,
Degradability, tensile elastic modulus 500-50,000k
A resin for packaging materials such as sheets and films that has g / cm ² and can be widely used as a general-purpose resin, a resin for foaming, a resin for extrusion molding, a resin for injection molding, a resin for ink, a resin for lamination, etc. A polymer useful as the above can be provided, and it is particularly useful as a method for producing a polymer for a packaging material.

The lactic acid-based copolyester of the present invention has T
Sheets and films can be easily processed by extrusion molding such as die-cast molding and inflation molding. Since lactic acid-based copolyester is highly hygroscopic, it is easily hydrolyzed, and when processing packaging materials such as sheets and films, it can be easily done with a general single-screw extruder, but water management is important. .

The screw has a normal L / D of 20 to 30.
It may be a full flight type, and a vent may be attached. When using a single-screw extruder, dehumidify and dry with a vacuum dryer etc. to avoid hydrolysis in the extruder,
It is preferable to control the water content in the raw material to 50 ppm or less.
The appropriate extrusion temperature varies depending on the molecular weight of the lactic acid-based copolyester to be used and the amount of residual lactide, but is preferably at least the flow initiation temperature.

In the T die cast molding, the sheet and film after extrusion are cooled with a mirror surface or a satin roll, which is usually temperature-controlled. At this time, an air knife can be used. Further, when a twin-screw extruder provided with a vent is used, the dehydration effect is high, and thus pre-drying is not required and efficient film formation is possible. At the time of inflation molding, molding can be easily performed with a molding device equipped with a normal circular die and an air ring, and no special auxiliary device is required. At this time, in order to avoid uneven thickness, the die, air ring or winder may be rotated.

The formed sheet or film can be uniaxially or biaxially stretched by a tenter system or an inflation system at a temperature not lower than the glass transition temperature and not higher than the melting point. By carrying out the stretching treatment, molecular orientation is caused and physical properties such as impact resistance, rigidity and transparency can be improved.

The stretching may be simultaneous stretching or sequential stretching, and the stretching speed is not particularly limited. The stretching ratio is not particularly limited, but in the case of biaxial stretching, stretching of usually 2 to 4 times in both the longitudinal and transverse directions is effective. In addition, especially when shrinkage property such as shrink film when heating is required,
High-strength stretching such as 3 to 6 times in the uniaxial or biaxial direction is preferable. Further, in order to improve heat resistance, heat setting may be carried out immediately after stretching to promote strain removal or crystallization to improve heat resistance.

When forming these sheets and films,
A general filler, for example, an inorganic filler such as talc, calcium carbonate, silica, clay, diatomaceous earth, perlite, or an organic filler such as wood powder may be mixed and added. In addition, 2,6-di-t-butyl-4-methylphenol (BHT), butyl hydroxyanisole (BH
It is possible to improve thermal stability during molding by using an antioxidant such as A), a salicylic acid derivative, a benzophenone-based or benzotriazole-based UV absorber, and a stabilizer such as phosphoric acid ester or carbodiimide. it can.

The addition amount of these stabilizers is not particularly limited, but the lactic acid-based polyether copolymer of the present invention alone has sufficient plasticity and has good melt moldability. To enhance softening, a plasticizer such as dioctyl adipate, dioctyl sebacate, trioctyl trimellitate, diethyl phthalate, dioctyl phthalate, polypropylene glycol adipic acid, butanediol adipate may be added. .

Among them, the adipic acid-based polyester plasticizer is particularly preferable in terms of moldability and flexibility, has a weight average molecular weight of 20,000 or less, and has polyester terminals sealed with alcohol or the like. The compatibility with the polymer is good and it is particularly preferable. The addition amount of these plasticizers is not particularly limited, for the purpose of avoiding bleeding, a phenomenon in which excess plasticizer is eluted from the resin,
1 to 30% by weight of high molecular weight lactic acid based polyester
Is preferably added in an amount of.

Metal soaps such as zinc stearate, magnesium stearate and calcium stearate,
Lubricants such as mineral oil, liquid paraffin, ethylene bis-stearyl amide, nonionic surfactants such as glycerin fatty acid ester and sucrose fatty acid ester, ionic surfactants such as alkyl sulfonate, titanium oxide, colorants such as carbon black Etc. may be added.

Further, by adding an inorganic foaming agent such as sodium bicarbonate or ammonium bicarbonate, an organic foaming agent such as azodicarbonamide, azobisisobutyronitrile or sulfonylhydrazide, or by adding pentane, butane,
A foaming agent such as freon may be impregnated in advance with the lactic acid-based copolymer of the present invention, or may be directly supplied into the extruder during the extrusion process to give a foam. It is also possible to make a multilayer with paper, aluminum foil, or other degradable polymer film by extrusion laminating, dry laminating or coextrusion.

As the secondary processing method of the sheet, a vacuum forming method, a pressure forming method, a vacuum pressure forming method and the like can be used. The lactic acid-based copolyester of the present invention can be formed into a sheet by using an existing apparatus used for producing a sheet of a general-purpose resin. In the case of vacuum forming or vacuum pressure forming, plug assist forming may be performed. The stretched sheet is preferably subjected to pressure molding. It should be noted that heating and cooling of the mold can be optionally used in combination during these moldings.
In particular, the heat resistance can be improved by heating the mold above the crystallization temperature and actively promoting the crystallization.

A general processing method can be applied to the secondary processing of the film, and the bag-like material is heat-sealed by an ordinary bag-making machine such as a horizontal pillow bag-making machine, a vertical pillow bag-making machine, and a twist-back bag-making machine. Obtainable. When obtaining processed products other than these sheets and films, molds such as containers can be obtained using an ordinary injection molding machine. Blow molding is also easy, and single-layer and multi-layer bottles can be easily molded by using an existing molding machine. There is no particular problem in press molding, and a single-layer or laminated product can be obtained by an ordinary molding machine.

The lactic acid-based polyether copolymer obtained in the present invention has good biodegradability, and even if it is discarded after being used for general-purpose resins, packaging materials, etc. or from the manufacturing process, Helps reduce the amount of waste. When it is dumped in the soil or seawater, it is hydrolyzed, decomposed by microorganisms, etc., and its strength as a resin deteriorates within a few months, and it can be decomposed before its outer shape is maintained. In addition, if compost is used, it will be biodegraded in a shorter period of time before its original shape is retained.

[0074]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The molecular weight of poly (oxyethylene-oxypropylene) polyol is measured by a terminal group quantitative method, and other molecular weights are measured by a GPC measuring device (hereinafter referred to as GPC).
The column temperature was 40 ° C. and the solvent was tetrahydrofuran, and the measurement was performed in comparison with a polystyrene standard sample.

The glass transition point and the melting point were measured by a differential scanning calorimeter (hereinafter abbreviated as DSC). Measurement condition is 10 ℃
The temperature was raised from 20 ° C. to 220 ° C./min. The tensile test was performed under the conditions of an initial sample length of 50 mm and a crosshead speed of 40 mm / min. The test piece is a hot press machine at a temperature of 160 to 180 ° C., 200 kg / cm ² , and 2 minutes.
It was cut into m × 80 mm length and measured.

The measurement conditions for the Vicat softening point are JI
It was measured according to the A method of SK 7206. Test pieces were made into dumbbells on a 1 ounce injection molding machine. In addition, the above-mentioned measurement used the equipment described below.

GPC: TOSOH HLC-8020
(Manufactured by Toso Corporation) DSC: DSC 200 (manufactured by Seiko Electronics Co., Ltd.) Tensile test: Tensilon (Toyo Seiki Co., Ltd.) Vicat softening point: HDT. VSPT. TESTER (Toyo Seiki Co., Ltd.)

The following abbreviations are used for the poly (oxyethylene-oxypropylene) polyols used in the examples, and the contents are shown below. EP-1: PEO and PPO linear block copolymer Mw = 4,050 (Newyole PE-75 manufactured by Sanyo Kasei Co., Ltd.) EP-2: Glycerin-type block copolymer of PEO and PPO Mw = 3 1,000 (Sanyox GL-3000 manufactured by Sanyo Kasei Co., Ltd.)

EP-3: trimethylpropane type block copolymer of PEO and PPO Mw = 3,000 (Sannix TL-4500 manufactured by Sanyo Chemical Industry Co., Ltd.) EP-4: glycerin type random copolymer of EO and PO Mw = 2,800 (Sanyo Chemical Co., Ltd. Sannix GEP-2800) EP-5: PEO and PPO linear block copolymer Mw = 20,000 (Sanyo Chemical Co., Ltd. Newpol PE-125) )

Example 1 A three-neck 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
P-1 (20 g), L-lactide (76 g), D-lactide (4 g) and toluene (15 ml) were charged, and under a nitrogen atmosphere, 1
The mixture was melted and mixed at 75 ° C. for 0.25 hours, and 0.03 g of tin octoate was added. After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid-based polyether copolymer obtained was transparent and had a number average molecular weight of 25,000 and a weight average molecular weight of 35,000 as measured by GPC. Glass transition temperature is about 53 ℃
The melting point was about 153 ° C. Further, the tensile breaking strain is 10%, the tensile breaking strength is 290 kgf / cm ² ,
The initial elastic modulus in tension was 5,000 kgf / cm ² , and the Vicat softening point was 45 ° C.

Example 2 A three-neck 200 ml separable flask equipped with a stirrer, a rectification column and a gas inlet tube was charged with E
P-1 (30 g), L-lactide (66.5 g), D-lactide (3.5 g) and toluene (15 ml) were charged, and the mixture was melted and mixed under a nitrogen atmosphere at 175 ° C. for 0.25 hours, and tin octanoate (0.03 g) was added. did. After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid type polyether copolymer obtained was transparent and had a number average molecular weight of 19,000 and a weight average molecular weight of 22,000 by GPC. Glass transition temperature is about 52 ℃
The melting point was about 152 ° C. Further, the tensile breaking strain is 50%, the tensile breaking strength is 210 kgf / cm ² ,
The initial elastic modulus in tension was 3,000 kgf / cm ² , and the Vicat softening point was 44 ° C. The obtained copolymer DSC chart, FT-IR chart, ¹ H-NMR chart,
¹³ C-NMR charts are shown in FIGS.

[Example 3] A three-necked 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
P-2 (10 g), L-lactide (85.5 g), D-lactide (4.5 g) and toluene (15 ml) were charged and melt-mixed under a nitrogen atmosphere at 175 ° C. for 0.25 hours, and 0.03 g of tin octanoate was added. . After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid type polyether copolymer obtained was transparent and had a number average molecular weight of 44,000 and a weight average molecular weight of 72,000 as measured by GPC. Glass transition point is about 54 ℃
The melting point was about 155 ° C. The tensile strain at break of 6%, a tensile break strength of 320 kgf / cm ^2, the tensile initial modulus 10,000kgf / cm ^2, Vicat softening point was 46 ° C..

Example 4 A three-neck 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
P-2 (30 g), L-lactide (66.5 g), D-lactide (3.5 g) and toluene (15 ml) were charged, and the mixture was melted and mixed under a nitrogen atmosphere at 175 ° C. for 0.25 hours, and 0.03 g of tin octanoate was added. did. After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid-based polyether copolymer obtained was transparent and had a number average molecular weight of 22,000 and a weight average molecular weight of 26,000 according to GPC. Glass transition point is about 49 ℃
The melting point was about 150 ° C. The tensile breaking strain is 120% and the tensile breaking strength is 240 kgf / cm.
² , the initial tensile elastic modulus was 2,000 kgf / cm ² , and the Vicat softening point was 43 ° C.

Example 5 A three-necked 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
5 g of P-3, 95 g of L-lactide, 15 m of toluene
In a nitrogen atmosphere at 175 ° C. for 0.25 hours,
After melting and mixing, 0.03 g of tin octoate was added.
After reacting for 5 hours, the produced copolymer was taken out.

The lactic acid-based polyether copolymer obtained was transparent and had a number average molecular weight of 71,000 and a weight average molecular weight of 110,000 as measured by GPC. Glass transition point is about 55
The melting point was about 157 ° C. The tensile breaking strain is 3%, the tensile breaking strength is 400 kgf / cm ² ,
The initial elastic modulus in tension was 15,000 kgf / cm ² , and the Vicat softening point was 46 ° C.

Example 6 A three-necked 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
40 g of P-3, 57 g of L-lactide, 3 g of D-lactide, and 15 ml of toluene were charged, and under a nitrogen atmosphere, 1
The mixture was melt-mixed at 75 ° C. for 0.25 hours, and 0.03 g of tin octoate was added. After reacting for 6 hours, the produced copolymer was taken out.

The lactic acid-based polyether copolymer obtained was transparent and had a number average molecular weight of 13,000 and a weight average molecular weight of 18,000 as measured by GPC. Glass transition point is about 47 ℃
The melting point was about 149 ° C. The tensile breaking strain is 180% and the tensile breaking strength is 200 kgf / cm.
² , the initial tensile elastic modulus was 1,800 kgf / cm ² , and the Vicat softening point was 41 ° C.

Example 7 A three-necked 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
20 g of P-4, 72 g of L-lactide, 8 g of D-lactide and 15 ml of toluene were charged, and under a nitrogen atmosphere, 1
The mixture was melted and mixed at 75 ° C. for 0.25 hours, and 0.03 g of tin octoate was added. After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid-based polyether copolymer obtained was transparent and had a number average molecular weight of 20,000 and a weight average molecular weight of 26,000 as determined by GPC. Glass transition point is about 50 ℃
The melting point was about 149 ° C. Further, the tensile breaking strain is 18%, the tensile breaking strength is 280 kgf / cm ² ,
The initial tensile elastic modulus was 7,800 kgf / cm ² , and the Vicat softening point was 44 ° C.

Example 8 A three-neck 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
P-4 (30 g), L-lactide (66.5 g), D-lactide (3.5 g) and toluene (15 ml) were charged, and the mixture was melt-mixed in a nitrogen atmosphere at 175 ° C. for 0.25 hours, and 0.03 g of tin octanoate was added. . After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid-based polyether copolymer obtained was transparent and had a number average molecular weight of 18,000 and a weight average molecular weight of 24,000 by GPC. Glass transition point is about 50 ℃
The melting point was about 146 ° C. The tensile breaking strain is 110% and the tensile breaking strength is 220 kgf / cm.
² , the initial tensile elastic modulus was 5,800 kgf / cm ² , and the Vicat softening point was 43 ° C.

The lactic acid-based polyether copolymer obtained in Example 2 was hot pressed to a thickness of 10 cm × 10 c.
m, 100 μm sheet was prepared. Press conditions, 16
The weight average molecular weight of the sheet obtained under the conditions of 5 ° C., 200 kg / cm ² and 2 minutes was 21,000. This sheet was embedded in soil and a biodegradation test was tried. The results are shown in Table 1.

[0098]

[Table 1]

Example 9 A three-neck 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with E
P-5 (10 g), L-lactide (85 g), D-lactide (5 g) and toluene (15 ml) were charged, and under a nitrogen atmosphere, 1
The mixture was melted and mixed at 75 ° C. for 0.25 hours, and 0.03 g of tin octoate was added. After reacting for 3 hours, the produced copolymer was taken out.

The lactic acid type polyether copolymer obtained was transparent and had a number average molecular weight of 55,000 and a weight average molecular weight of 95,000 as measured by GPC. Glass transition temperature is about 51 ℃
The melting point was about 155 ° C. Further, the tensile breaking strain is 28%, the tensile breaking strength is 270 kgf / cm ² ,
The initial elastic modulus in tension was 10,000 kgf / cm ² , and the Vicat softening point was 45 ° C.

Example 10 The pellets obtained in Example 5 were thoroughly dried and then extruded at a temperature of 160 ° C.
L / D = 24 Extrusion screw Extruder (made by Tanabe Plastic Co., Ltd.) with a diameter of 50 mm, thickness 0.1
A sheet having excellent transparency of 5 mm was obtained. The extrusion conditions are a screw rotation speed of 24 rpm and a discharge rate of 15 kg / h.
r, back pressure 72 kg / cm ² , take-up speed 6.0 m / m
It was in.

[Embodiment 11]
A 15 mm sheet was formed by a vacuum forming machine (manufactured by Sanwa Kogyo Co., Ltd.). When the side dish tray was molded under the conditions of heating time of 5 seconds, molding / cooling time of 5 seconds, and mold releasing time of 1 second, a molded product excellent in mold reproducibility and transparency could be obtained.

Example 12 The pellet obtained in Example 3 was sufficiently dried, and then a blow molding machine (manufactured by Japan Steel Works, Ltd.) using an extruder with L / D = 25 and a screw diameter of 40 mm. By blow molding, a 60 ml bottle having excellent mold reproducibility and transparency was obtained. Molding conditions are: cylinder temperature 160-170 ℃, cylinder head temperature 170 ℃,
The mold temperature was 32 ° C., the discharge rate was 4.2 kg / hr, and 3 kgf / cm ² of air was blown from the die core.

Example 13 The pellets obtained in Example 1 were thoroughly dried and then extruded with a 50 mm extruder equipped with a die having a width of 400 mm to obtain a basis weight of 200 g / m ^2.
Laminated to paper. Molding conditions are cylinder temperature 15
0 to 200 ° C, die temperature 200 ° C, cooling roll temperature 60
℃, discharge rate 4kg / h, line speed 10m / min
Met. The obtained paper laminae were excellent in film thickness uniformity and had good laminate strength of 370 g / 15 mm or more.

[Comparative Example 1] In a three-neck 200 ml separable flask equipped with a stirrer, a rectification column, and a gas introduction tube, 30 g of polyethylene glycol having a molecular weight of 2,000 and L were added.
-To 66.5 g of lactide, 3.5 g of D-lactide,
Toluene (15 ml) was added, and under a nitrogen gas atmosphere, 175
The mixture was dissolved and mixed at 0 ° C. for 0.25 hours, 0.03 g of tin octoate was added as a ring-opening polymerization catalyst, and polymerization was carried out for 3 hours. After the reaction, toluene was removed under reduced pressure.

The produced lactic acid-based copolymer was a colorless and transparent resin having a weight average molecular weight of 13,000 and a number average molecular weight of 11,000. It had a glass transition point of about 32 ° C. and a melting point of about 146 ° C. The tensile strain at break of 10%, a tensile break strength of 180 kgf / cm ^2, the tensile initial modulus of 3,000kgf / cm ^2, Vicat softening point was 32 ° C..

[Comparative Example 2] A 3-neck 200 ml separable flask equipped with a stirrer, a rectification column, and a gas inlet tube was charged with 30 g of polypropylene glycol having a molecular weight of 3,000.
L-lactide 66.5g, D-lactide 3.5g
To the above, add 15 ml of toluene, and in a nitrogen gas atmosphere, 1
The mixture was dissolved and mixed at 75 ° C. for 0.25 hours, 0.03 g of tin octoate was added as a ring-opening polymerization catalyst, and polymerization was carried out for 3 hours.

After the reaction, toluene was removed under reduced pressure. The produced lactic acid-based copolymer has a weight average molecular weight of 16,000,
It was a white resin having a number average molecular weight of 13,000. It had a glass transition point of about 36 ° C and a melting point of about 148 ° C. The tensile breaking strain is 25% and the tensile breaking strength is 210.
kgf / cm ² , initial tensile elastic modulus is 6,000 kgf /
cm ² , Vicat softening point was 33 ° C. The results of these Examples and Comparative Examples are shown in Tables 2 to 4.

[0109]

[Table 2]

[0110]

[Table 3]

[0111]

[Table 4]

[0112]

INDUSTRIAL APPLICABILITY The present invention has a biodegradable lactic acid-based polyether copolymer having a sufficient high molecular weight, heat resistance and heat stability, and having rigidity, flexibility and transparency according to the use, It is possible to provide a manufacturing method and a molded article made of the resin composition.

[Brief description of drawings]

FIG. 1 is a DSC chart of the lactic acid-based polyether copolymer obtained in Example 2.

FIG. 2 is an FT-IR chart of the lactic acid-based polyether copolymer obtained in Example 2.

FIG. 3 is a ¹ H-NMR chart of the lactic acid-based polyether copolymer obtained in Example 2.

FIG. 4 is a ¹³ C-NMR chart of the lactic acid-based polyether copolymer obtained in Example 2.

Claims (9)

[Claims] 1. A polylactic acid segment (A) having a weight average molecular weight of 70 to 100,000 and a weight average molecular weight of 100 to 100.
A weight average molecular weight of 1 having a repeating unit consisting of 20,000 polyethylene oxide segments (B) and a polypropylene oxide segment (C) having a weight average molecular weight of 100 to 20,000, and having a polylactic acid segment (A) at the end. 1,000 to 150,000 lactic acid-based polyether copolymer resin composition. 2. A repeating unit comprising a polylactic acid segment (A), a polyethylene oxide segment (B) and a polypropylene oxide segment (C) is A
(-B-C-) _n- A, (where n = 1 to 200), and the polylactic acid segment (A) and the polyethylene oxide segment (B) or the polypropylene oxide (C) are bound by an ester bond. The lactic acid-based polyether copolymer resin composition according to claim 1, wherein the polyethylene oxide segment (B) and the polypropylene oxide segment (C) are bound by an ether bond. 3. A repeating unit comprising a polylactic acid segment (A), a polyethylene oxide segment (B) and a polypropylene oxide segment (C) is A
(-B-C-B-) _n- A, (where n = 1 to 130)
And the polylactic acid segment (A) and the polyethylene oxide segment (B) are bound by an ester bond,
The lactic acid-based polyether copolymer resin composition according to claim 1, wherein the polyethylene oxide segment (B) and the polypropylene oxide segment (C) are bound by an ether bond. 4. A repeating unit comprising a polylactic acid segment (A), a polyethylene oxide segment (B) and a polypropylene oxide segment (C) is A
(-C-B-C-) _n- A, (where n = 1 to 130)
And the polylactic acid segment (A) and the polypropylene oxide segment (C) are bound by an ester bond, and the polyethylene oxide segment (B) and the polypropylene oxide segment (C) are bound by an ether bond. The lactic acid-based polyether copolymer resin composition according to claim 1. 5. A lactide (D) and a poly (oxyethylene-oxypropylene) polyol (E) in a weight ratio (D) / (E) = 50/50 to 97/3 in the presence of a polymerization catalyst. Copolymerization with
A method for producing the lactic acid-based polyether copolymer resin composition according to any one of 1. 6. A poly (oxyethylene-oxypropylene) polyol (E) is a repeating unit (—B—C—) _n , where n is a polyethylene oxide segment (B) and a polypropylene oxide segment (C). = 1 to 200), including a weight average molecular weight of 200 to 4
The method for producing a lactic acid-based polyether copolymer resin composition according to claim 5, wherein the lactic acid-based polyether copolymer resin composition is 50,000 polyol. 7. A poly (oxyethylene-oxypropylene) polyol (E) is a repeating unit (—B—C—B—) _n consisting of a polyethylene oxide segment (B) and a polypropylene oxide segment (C),
(Where n = 1 to 130), including weight average molecular weight 30
The method for producing a lactic acid-based polyether copolymer resin composition according to claim 5, wherein the polyol is 0 to 40,000. 8. A poly (oxyethylene-oxypropylene) polyol (E) is a repeating unit (—C—B—C—) _n consisting of a polyethylene oxide segment (B) and a polypropylene oxide segment (C),
(Where n = 1 to 130), including weight average molecular weight 30
The method for producing a lactic acid-based polyether copolymer resin composition according to claim 5, wherein the polyol is 0 to 40,000. 9. A molded article comprising the lactic acid-based polyether copolymer resin composition according to claim 1.