JP7094590B1 - Resin composition and molded product - Google Patents

Abstract

An object of the present invention is to provide a biodegradable resin-containing composition that has good moldability, excellent mechanical properties, particularly excellent elongation at break, and that can give molded articles that are less likely to deteriorate in appearance due to bleeding. to provide. The present invention contains a biodegradable resin, heavy calcium carbonate, and an epoxy compound, and the mass ratio of the biodegradable resin to the heavy calcium carbonate is 10:90 to 70:30, The biodegradable resin includes at least polybutylene adipate terephthalate or polybutylene succinate adipate, and the epoxy compound includes epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized palm oil, bisphenol A type epoxy resin, and a bisphenol F type epoxy resin, and the content of the epoxy compound is 2% by mass or more and 8% by mass or less with respect to 100% by mass of the resin composition. offer things. [Selection figure] None

Description

The present invention relates to a resin composition and a molded product.

Biodegradable resins are attracting attention as environmentally friendly resins because they are decomposed into substances that originally exist in nature by the action and hydrolysis of microorganisms. It has been proposed to add various components to the biodegradable resin in order to impart various properties and the like to the biodegradable resin without impairing the small environmental load (for example, Patent Documents 1, 2 and the like). Examples of such a component include calcium carbonate and the like.

In a biodegradable resin composition containing a high amount of calcium carbonate, there is a possibility that the mechanical properties of the molded product obtained by molding the composition, particularly the elongation at the time of cutting, may decrease. Above all, in a resin composition in which a large amount of calcium carbonate is added to a biodegradable resin such as polybutylene adipate terephthalate, for example, about 30% by mass or more, it is difficult to mold, and hydrolysis proceeds during molding to promote mechanical properties and molded products. The surface appearance of the product is deteriorated, and even when a molded product that can withstand practical use cannot be obtained. As a technique for improving the mechanical properties of the resin composition, it has been proposed to add a plasticizer such as citric acid ester or glycerol (for example, Patent Documents 3 and 4 and the like). Further, Patent Document 5 discloses a resin composition in which polybutylene adipate terephthalate or polybutylene succinate adipate and heavy calcium carbonate are combined.

Japanese Unexamined Patent Publication No. 2017-119850 Special Table 2018-527416 Gazette Special Table 2020-531678 Gazette Japanese Unexamined Patent Publication No. 2020-1834496 Japanese Patent No. 6916571

Although the elongation at the time of cutting can be improved to some extent by blending the plasticizer, bleeding of the plasticizer may occur and the surface appearance of the molded product may be deteriorated. If the amount of the plasticizer is suppressed to prevent bleeding, the mechanical properties are not significantly improved and the moldability is difficult to be improved. Therefore, the amount of calcium carbonate or the like added must be reduced. Also in the resin compositions described in Patent Documents 3 and 4, the content of calcium carbonate is limited to 20% by mass or less, and further to about 10% by mass or less. The resin composition described in Patent Document 5 contains about 30 to 90% by mass of heavy calcium carbonate and suppresses bleeding, but further improvement in elongation during cutting is required depending on the application.

The present invention has been made in view of the above circumstances, and it is possible to obtain a molded product having good molding processability, excellent mechanical properties, particularly elongation at the time of cutting, and less likely to deteriorate in appearance due to bleeding. An object of the present invention is to provide a resin composition containing a sex resin.

The present inventor solves the above-mentioned problems by using a biodegradable resin containing at least polybutylene adipate terephthalate or polybutylene succinate adipate, combining this with heavy calcium carbonate, and further blending a predetermined amount of a specific epoxy compound. We found what we could do and completed the present invention. More specifically, the present invention provides the following.

(1) A resin composition containing a biodegradable resin, heavy calcium carbonate, and an epoxy compound.
The mass ratio of the biodegradable resin to the heavy calcium carbonate is 10:90 to 70:30.
The biodegradable resin comprises at least polybutylene adipate terephthalate or polybutylene succinate adipate.
The epoxy compound is one or more compounds selected from the group consisting of epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized palm oil, bisphenol A type epoxy resin, and bisphenol F type epoxy resin. can be,
The content of the epoxy compound is 2.0% by mass or more and 8.0% by mass or less with respect to 100% by mass of the resin composition.
Resin composition.

(2) The resin composition according to (1), wherein the epoxy compound is a compound having an epoxy equivalent of 100 g / eq or more and 200 g / eq or less.

(3) The resin composition according to (1) or (2), which contains the biodegradable resin and the heavy calcium carbonate in a mass ratio of 10:90 to 50:50.

(4) The biodegradable resin is composed of polybutylene adipate terephthalate and polylactic acid.
The mass ratio of the polybutylene adipate terephthalate to the polylactic acid is 50:50 to 90:10.
The resin composition according to any one of (1) to (3).

(5) The biodegradable resin is composed of polybutylene succinate adipate and polylactic acid.
The mass ratio of the polybutylene succinate adipate to the polylactic acid is 50:50 to 90:10.
The resin composition according to any one of (1) to (3).

(6) Further containing 5% by mass or more and 30% by mass or less of natural organic substances with respect to 100% by mass of the resin composition.
The natural organic matter is one or more selected from the group consisting of cellulose powder, wood flour, starch, fir husks, okara, and bran.
The resin composition according to any one of (1) to (5).

(7) The above-mentioned (1) to (6), wherein the average particle size of the heavy calcium carbonate by the air permeation method according to JIS M-8511 is 0.7 μm or more and 6.0 μm or less. Resin composition.

(8) The resin composition according to any one of (1) to (7), further containing acetyltributyl citrate in an amount of 5% by mass or more and 20% by mass or less with respect to 100% by mass of the resin composition. ..

(9) A molded product obtained from the resin composition according to any one of (1) to (8).

(10) The molded product according to (9), wherein the molded product is an inflation film.

(11) The molded product according to (9), wherein the molded product is an extruded sheet.

According to the present invention, there is provided a biodegradable resin-containing composition capable of obtaining a molded product having good molding processability, excellent mechanical properties, particularly elongation at the time of cutting, and less likely to deteriorate in appearance due to bleeding. To.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

<Resin composition>
The resin composition of the present invention is a resin composition containing a biodegradable resin, heavy calcium carbonate, and an epoxy compound.
The mass ratio of the biodegradable resin to the heavy calcium carbonate is 10:90 to 70:30.
The biodegradable resin comprises at least polybutylene adipate terephthalate or polybutylene succinate adipate.
The epoxy compound is one or more compounds selected from the group consisting of epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized palm oil, bisphenol A type epoxy resin, and bisphenol F type epoxy resin. can be,
The content of the epoxy compound is 2.0% by mass or more and 8.0% by mass or less with respect to 100% by mass of the resin composition.

Polybutylene adipate terephthalate (PBAT) and polybutylene succinate adipate (PBSA) have good biodegradability.
It is known that a biodegradable resin composition containing calcium carbonate together with such a biodegradable resin can impart good properties (tearability, etc.) to a molded product obtained from the composition. ..

However, the present inventor first said that when the amount of calcium carbonate in the biodegradable resin composition is large, the tensile strength and elongation at the time of cutting in the molded product obtained from the composition are likely to be impaired, and as calcium carbonate. It has been found that by selecting heavy calcium carbonate, it is possible to suppress a decrease in tensile strength and elongation at the time of cutting.

The present inventor has further studied, and by blending a specific epoxy compound in a relatively small amount, the moldability is improved and the deterioration of the mechanical properties of the molded product is suppressed, and in particular, the elongation at the time of cutting is greatly improved. Moreover, it was found that the appearance deterioration due to bleeding is unlikely to occur.

As will be described later, a part of this type of epoxy compound may be blended in the resin composition as a plasticizer in an amount of about 10 to 30% by mass, but this time, a small amount of 8.0% by mass or less has mechanical properties. In particular, we obtained an unexpected finding that the elongation at the time of cutting is greatly improved. The reason for this is not clear, and the present invention is not limited by a specific theory, but it is possible that the epoxy compound blended in the present invention reacts with the decomposition product of the biodegradable resin as described later. Sex is possible.

In the present invention, "biodegradability" means the property of being decomposed by the action of microorganisms or hydrolysis, and can be evaluated by the method shown in Examples.

In the present invention, the "tensile strength" means a value obtained by dividing the maximum load reached up to the fracture by the cross-sectional area before the tensile load when the object is broken by applying a tensile load. It can be evaluated by the method shown in the examples.

In the present invention, the "elongation at the time of cutting" means the elongation at the time of breaking when the object is broken by applying a tensile load, and can be evaluated by the method shown in the examples.

In the present invention, words such as "improved mechanical properties" and "suppressed reduction in tensile strength and elongation during cutting" are used in the molded product obtained from the resin composition satisfying the requirements of the present invention. Characteristic values of molded products obtained from resin compositions that do not meet the requirements of the present invention except that at least one of the mechanical properties such as tensile strength and elongation during cutting has the same type and blending amount of biodegradable resin. It means that it is equal to or higher than.

Hereinafter, the structure of the resin composition of the present invention will be described.

(Type of biodegradable resin)
The biodegradable resin in the present invention contains at least polybutylene adipate terephthalate (hereinafter, also referred to as “PBAT”) or polybutylene succinate adipate (hereinafter, also referred to as “PBSA”). That is, the biodegradable resin in the invention may contain only PBAT or PBSA, or may contain both.

The biodegradable resin in the present invention may or may not contain a biodegradable resin other than PBAT and PBSA.

Examples of biodegradable resins other than PBAT and PBSA that can be contained in the resin composition of the present invention include polylactic acid, polyhydroxybutyrate, and poly (3-hydroxybutyrate-co-3-hydroxyhexanoate). , Polycaprolactone, polybutylene succinate, polyethylene succinate, polyapple acid, polyglycolic acid, polydioxanone, poly (2-oxetanone) and the like. Of these, polylactic acid is preferable from the viewpoint of easily exhibiting the effects of the present invention.

In the present invention, "polylactic acid" refers to a polylactic acid homopolymer obtained by polycondensing only a lactic acid component as a raw material monomer, and a lactic acid component as a raw material monomer and other monomer components copolymerizable with the lactic acid component. Includes a polylactic acid copolymer obtained by polycondensing and.
In the present invention, any polymer known as polylactic acid can be used.

Other monomer components that can be copolymerized with lactic acid are not particularly limited, but are, for example, oxyacids, dihydric alcohols, trihydric or higher polyhydric alcohols, aromatic hydroxy compounds, divalent carboxylic acids, and trivalents. Examples thereof include the above-mentioned polyvalent carboxylic acids and lactones.

Examples of the oxy acid include oxy acids such as glycolic acid, hydroxypropionic acid, hydroxy fatty acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxybenzoic acid and hydroxyheptanoic acid.

Examples of the dihydric alcohols include ethylene glycol, propylene glycol, propanediol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentylglycol, and diethylene glycol. Examples thereof include triethylene glycol, polyethylene glycol, polytetramethylene glycol and the like.

Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, pentaerythritol and the like.

Examples of the aromatic hydroxy compound include hydroquinone, resorcin, bisphenol A and the like.

Examples of the divalent carboxylic acid include oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecandioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid and naphthalenedicarboxylic acid. Examples thereof include acid, bis (4-carboxyphenyl) methane, anthracendicarboxylic acid, bis (4-carboxyphenyl) ether, sodium 5-sulfoisophthalate and the like.

Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid and pyromellitic acid.

Examples of the lactones include caprolactone, valerolactone, propiolactone, undecalactone, 1,5-oxepane-2-one and the like.

(Composition of biodegradable resin)
The composition of the biodegradable resin is not particularly limited as long as it contains at least PBAT and PBSA, but any of the following embodiments is particularly preferable.
(Aspect 1) The biodegradable resin is made of PBAT.
(Aspect 2) The biodegradable resin is made of PBSA.
(Aspect 3) The biodegradable resin comprises PBAT and PBSA.
(Aspect 4) The biodegradable resin comprises PBAT and / or PBSA and polylactic acid.

In the present invention, "the biodegradable resin is made of the resin X" means that only the resin X is contained as the biodegradable resin in the resin composition.

Regarding the above (Aspect 3), the compounding ratio of PBAT and PBSA is not particularly limited, but the mass ratio of PBAT and PBSA is preferably PBAT: PBSA = 10: 90 to 90:10.

Regarding the above (Aspect 4), the compounding ratio of PBAT and PBSA and polylactic acid is not particularly limited, but the mass ratio of PBAT and PBSA (total amount) to polylactic acid is preferably PBAT and PBSA: polylactic acid = 50. : 50 to 90:10.

Regarding the above (Aspect 4), the compounding ratio of PBAT and polylactic acid is not particularly limited, but the mass ratio of PBAT and polylactic acid is preferably PBAT: polylactic acid = 50: 50 to 90:10.

Regarding the above (Aspect 4), the compounding ratio of PBSA and polylactic acid is not particularly limited, but the mass ratio of PBSA and polylactic acid is preferably PBSA: polylactic acid = 50: 50 to 90:10.

(Heavy calcium carbonate)
In the present invention, "heavy calcium carbonate" is obtained by mechanically pulverizing natural calcium carbonate or the like, and is a synthetic calcium carbonate (that is, light calcium carbonate) produced by a chemical precipitation reaction or the like. Is clearly distinguished.

Heavy calcium carbonate is obtained, for example, by crushing and classifying natural calcium carbonate such as calcite (limestone, chalk, marble, etc.), shells, coral and the like.

As the pulverization method in the method for producing heavy calcium carbonate, either wet pulverization or dry pulverization can be adopted. From an economical point of view, dry pulverization that does not require a dehydration step or a drying step is preferable.
The crusher used for crushing is not particularly limited, and examples thereof include an impact type crusher, a crusher using a crushing medium (ball mill, etc.), a roller mill, and the like.

For the classification in the method for producing heavy calcium carbonate, conventionally known means such as air classification, wet cyclone, and decanter can be adopted.

The heavy calcium carbonate may or may not be surface-treated. The surface treatment can be performed at any time point (before pulverization, during pulverization, before classification, after classification, etc.) in the method for producing heavy calcium carbonate.

Examples of the surface treatment of heavy calcium carbonate include a physical method (plasma treatment and the like) and a chemical method (a method using a coupling agent, a surfactant and the like).

Among the surface treatments of heavy calcium carbonate, examples of the coupling agent used in the chemical method include a silane coupling agent and a titanium coupling agent.

Among the surface treatments of heavy calcium carbonate, examples of the surfactant used in the chemical method include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. More specifically, for example, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid salts and the like can be mentioned.

By applying the above surface treatment, the dispersibility of heavy calcium carbonate can be enhanced.
However, heavy calcium carbonate that has not been surface-treated is preferable because it can reduce the risk of odor generation due to thermal decomposition of the surface treatment agent during molding.

The form of the heavy calcium carbonate is not particularly limited, but is preferably particulate from the viewpoint of good dispersibility in the resin composition.

When the heavy calcium carbonate is in the form of particles, its average particle size is preferably 0.7 μm or more and 6.0 μm or less, more preferably 1.0 μm or more and 5.0 μm or less, and further preferably 1.5 μm or more and 3.0 μm. It is as follows.
When the average particle size of the heavy calcium carbonate is in the above range, the dispersibility in the resin composition is good, and an excessive increase in viscosity of the resin composition can be prevented. Further, the heavy calcium carbonate particles are less likely to protrude from the surface of the molded product obtained from the resin composition and fall off, or the surface texture, mechanical strength, etc. are not impaired, and the effect of the present invention can be more easily exerted.

In the present invention, the "average particle size" means a value calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511.
As a measuring device for the average particle size, for example, a specific surface area measuring device “SS-100 type” manufactured by Shimadzu Corporation can be preferably used.

When the heavy calcium carbonate is in the form of particles, it is preferable that the particle size distribution does not include particles having a particle size of 45 μm or more.

When the heavy calcium carbonate is in the form of particles, its irregularity can be expressed by the degree of spheroidization of the shape, that is, the roundness. The lower the roundness, the higher the indeterminate form.
When the heavy calcium carbonate is in the form of particles, its roundness is preferably 0.50 or more and 0.95 or less, more preferably 0.55 or more and 0.93 or less, and further preferably 0.60 or more and 0.90. It is as follows.

In the present invention, "roundness" is a value obtained by dividing the projected area of a particle by the area of a circle having the same peripheral length as the projected peripheral length of the particle ((projected area of the particle) / (projected peripheral length of the particle). It means the area of a circle with the same perimeter)).
The method for measuring the roundness is not particularly limited, and for example, it can be specified by analyzing a projection drawing of particles obtained by a scanning microscope, a stereomicroscope, or the like with commercially available image analysis software.
Specifically, the projected area of the particle (A), the area of the circle having the same perimeter as the projected perimeter of the particle (B), the radius (r) of the circle having the same perimeter as the projected perimeter of the particle, and the particle. It can be calculated by the following formula based on the measurement result of the projected perimeter (PM) of.
"Roundness" = A / B = A / πr ² = A × 4π / (PM) ²

(Composition of resin composition)
In the composition of the resin composition of the present invention, the mass ratio of the biodegradable resin to the heavy calcium carbonate is biodegradable resin: heavy calcium carbonate = 10: 90 to 70:30, and a specific epoxy. It is not particularly limited except that the compound is contained in an amount of 2.0 to 8.0% by mass.
According to the present invention, despite the high content of heavy calcium carbonate as described above, the moldability is excellent, the mechanical properties, particularly the elongation at the time of cutting, is good, and bleeding to the surface of the molded product is unlikely to occur. It is possible to provide a resin composition that gives an article.

In the resin composition of the present invention, the mass ratio of the biodegradable resin to the heavy calcium carbonate is preferably biodegradable resin: heavy calcium carbonate = 10: 90 to 50:50, and 20: 80 to 50:50. Is more preferable, and 30:70 to 50:50 is even more preferable.

The upper limit of the content of the biodegradable resin is preferably 70% by mass or less, more preferably 50% by mass or less, based on the resin composition.

The lower limit of the content of the biodegradable resin is preferably 10% by mass or more, more preferably 20% by mass or more, based on the resin composition.

The upper limit of the content of heavy calcium carbonate is preferably 90% by mass or less, more preferably 80% by mass or less, based on the resin composition.

The lower limit of the content of heavy calcium carbonate is preferably 30% by mass or more, more preferably 50% by mass or more, based on the resin composition.

(Epoxy compound)
In addition to the biodegradable resin and heavy calcium carbonate described above, the resin composition of the present invention comprises epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized palm oil, bisphenol A type epoxy resin, and One or more epoxy compounds selected from the group consisting of bisphenol F type epoxy resins are contained in an amount of 2.0% by mass or more and 8.0% by mass or less with respect to 100% by mass of the resin composition.

Epoxidized soybean oil, epoxidized flax oil, epoxidized castor oil, and epoxidized palm oil are known and commercially available. All are epoxidized vegetable oils such as soybean oil, flaxseed oil, castor oil, and palm oil. In the present specification, epoxidized soybean oil, epoxidized flaxseed oil, epoxidized castor oil, and epoxidized palm oil may be collectively referred to as "epoxidized vegetable oil".

These epoxidized vegetable oils are made from natural oils, and the degree of epoxidation also varies between varieties, lots, and molecules within the same lot, so their structures and molecular weights vary widely. Over. In addition, there are cases where soybean oil or oil not made only from flax is supplied as "epoxidized soybean oil" because it has a similar structure. Such an epoxidized product is also an epoxy compound used in the present invention. Included in. The following is an example of typical chemical structures of epoxidized soybean oil and epoxidized flaxseed oil, but the epoxidized vegetable oil that can be used in the present invention is not limited thereto.

An example of the typical chemical structure of epoxidized soybean oil:

An example of the typical chemical structure of epoxidized flax oil:

The molecular weights of the epoxidized soybean oil and the epoxidized flaxseed oil represented by the above formula are 960 and 974, respectively. In the present invention, an epoxidized vegetable oil having any molecular weight can be used, but in consideration of the balance between the molding processability of the resin composition and the mechanical properties of the molded product, the average molecular weight is preferably about 500 to 2000. , More preferably about 700 to 1500, and particularly preferably about 800 to 1200.

Bisphenol A type epoxy resin and bisphenol F type epoxy resin are also known, and various varieties of general-purpose resin materials are commercially available. The epoxy resin is a general term for thermosetting resins that can be cured by cross-linking the epoxy groups remaining in the polymer. In a broad sense, both the prepolymer before cross-linking and curing and the resin after curing are included, but in the present invention, the prepolymer is used. Hereinafter, the bisphenol A type epoxy resin and the bisphenol F type epoxy resin may be collectively referred to as "prepolymer". These prepolymers can generally be obtained by copolymerizing bisphenol A or bisphenol F with epichlorohydrin, and various varieties depending on the polymerization state are on the market. Their typical chemical structures are shown below.

An example of a typical chemical structure of bisphenol A type epoxy resin:

An example of a typical chemical structure of bisphenol F type epoxy resin:

Generally, these prepolymers tend to become solid at room temperature when "n" in the above formula is 2 to 3 or more and the molecular weight is about 700 to 1000 or more. Although any form of prepolymer can be used in the present invention, a liquid prepolymer is preferable from the viewpoint of improving the flexibility of the resin composition. More preferably, a prepolymer having "n" of 1 or less, particularly 0 is used.

The above-mentioned prepolymer is often used as a main raw material of a thermosetting resin, that is, as a component usually occupying 50% by mass or more, or 70% by mass or more. Further, the above-mentioned epoxidized vegetable oil is often used as a resin plasticizer, and is usually blended in a resin composition in an amount of about 10 to 30% by mass. However, in the resin composition containing PBAT or PBSA and heavy calcium carbonate as main components as in the present invention, these epoxy compounds are 2.0% by mass or more and 8.0% by mass with respect to 100% by mass of the resin composition. By blending in a relatively small amount of the following, mechanical properties such as elongation during cutting are greatly improved. This is a completely unexpected finding.

Although the present invention is not limited by a specific theory, it is possible that the epoxy compound reacts with the decomposition products of PBAT and PBSA as the reason why the present invention is effective. In general, ester resins such as PBAT and PBSA reduce their molecular weight by hydrolysis to produce decomposition products having carboxylic acid terminals. When the epoxy compound coexists here, as a result of reacting with the carboxy group of the produced decomposition product, the decrease in the molecular weight of the resin is suppressed, and the reaction product can also function as a high molecular weight plasticizer. Furthermore, as a result of the carboxylic acid generated by the decomposition of the resin reacting with the epoxy compound, the risk of accelerated hydrolysis of PBAT and PBSA is also reduced. The reason why the elongation at the time of cutting can be greatly improved as shown in the examples described later, even if the blending amount is 2.0 to 8.0% by mass, which is usually not obtained by the large plasticizing effect of the liquid component blending. Is thought to be for that reason. Unlike ordinary plasticizers, the advantage that it is difficult to bleed on the surface of the molded product can be considered to be that a part of the compounded epoxy compound binds to the polymer component.

As described above, the molecular weight and chemical structure of the epoxidized vegetable oil and the prepolymer to be blended in the resin composition of the present invention are not particularly limited, but the epoxy equivalent is preferably a compound having an epoxy equivalent of 100 g / eq or more and 200 g / eq or less. .. When the epoxy equivalent is 200 g / eq or less, even if the compounding amount is small, a sufficient amount of epoxy group with respect to the biodegradable resin coexists in the resin composition, so that the epoxy group coexists with the hydrolyzate of PBAT or PBSA. By reacting, it is possible to suppress the reduction in molecular weight and improve the mechanical properties of the molded product. In addition, since the blending amount can be reduced, the risk of bleeding on the surface of the molded product is also reduced. If the epoxy equivalent is 100 g / eq or more, various products are on the market, which is advantageous in terms of cost. The epoxy equivalent of the epoxy compound is more preferably 120 g / eq or more and less than 200 g / eq, and particularly preferably 150 g / eq or more and 190 g / eq or less.

Further, in order to enhance the effect of improving the mechanical properties by containing the epoxy compound, the content of these epoxy compounds is preferably 2.2% by mass or more, preferably 2.5% by mass, based on 100% by mass of the resin composition. The above is more preferable, and 3.0% by mass or more is particularly preferable.

On the other hand, from the viewpoint of reducing the risk of the epoxy compound bleeding on the surface of the molded product, the content of these epoxy compounds is preferably 6.0% by mass or less with respect to 100% by mass of the resin composition. It is more preferably less than 0% by mass, further preferably 4.5% by mass or less, and particularly preferably 4.0% by mass or less. In particular, an epoxy compound having an epoxy equivalent of more than 200 g / eq may bleed on the surface of the molded product if it is blended in a large amount, so the content is preferably less than 5.0% by mass.

(Other components in the resin composition)
The resin composition of the present invention may further contain any component in addition to the above components as long as the effect of the present invention is not impaired. Such components can be used alone or in combination of two or more. In addition, the type and blending amount of such a component can be appropriately set according to the effect to be obtained and the like.

The components that can be contained in the resin composition of the present invention include plasticizers, natural organic substances, resins other than biodegradable resins, antistatic agents, fillers (other than heavy calcium carbonate), colorants, lubricants, and antioxidants. , Flame retardants, foaming agents and the like.

[Plasticizer]
Examples of the plasticizer include acetyltributyl citrate, triethyl citrate, acetyltriethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, o. -Benzoylbenzoic acid ester, diacetin and the like can be mentioned. Further, the epoxy compound such as the above-mentioned epoxidized soybean oil can also be used as a plasticizer.

Among the above plasticizers, acetyltributyl citrate, in combination with heavy calcium carbonate, particularly suppresses a decrease in the tensile strength and elongation during cutting of the molded product without impairing the biodegradability of the biodegradable resin. It has the advantage of being easy.

The upper limit of the content of the plasticizer is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, based on the resin composition of the present invention.

Since the resin composition of the present invention has improved mechanical properties such as elongation at cutting by the action of the epoxy compound contained therein and has flexibility, it is not necessary to separately add a plasticizer, but a plasticizer is added. In this case, the lower limit of the content is preferably 5.0% by mass or more, more preferably 7.5% by mass or more, based on the resin composition of the present invention.

When acetyltributyl citrate is used as the plasticizer, the upper limit of the content thereof is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, based on the resin composition of the present invention.

When acetyltributyl citrate is used as the plasticizer, the lower limit of the content thereof is preferably 5.0% by mass or more, more preferably 7.5% by mass or more, based on the resin composition of the present invention.

[Natural organic matter]
As the natural organic matter, any component that can be blended in the resin composition can be used.

Of the natural organics, one or more selected from the group consisting of cellulose powder, wood flour, starch, fir husks, okara, and bran impairs the biodegradability of biodegradable resins in combination with heavy calcium carbonate. It has the advantage that it is particularly easy to suppress a decrease in the tensile strength of the molded product and the elongation at the time of cutting.

In the present invention, the "cellulose powder" is not particularly limited as long as it is powdered cellulose.
The average particle size of the cellulose powder is preferably 5 μm or more and 45 μm or less, and more preferably 10 μm or more and 30 μm or less.
A commercially available product may be used as the cellulose powder.

In the present invention, the "wood powder" is not particularly limited as long as it is a powder obtained from any tree (cypress, sugi, etc.).
The average particle size of the wood powder is preferably 20 μm or more and 300 μm or less, and more preferably 20 μm or more and 45 μm or less.
As the wood powder, for example, what is known as "sawdust" can be used.

In the present invention, the "starch" can be any form that can be blended with the resin. The starch may be in the form of powder, for example.

In the present invention, the "fir shell" means the outermost skin of paddy, and any form that can be blended with the resin can be used. The fir shell may be in the form of powder, for example.

In the present invention, "okara" means a squeezed residue of soymilk, and any form that can be blended with a resin can be used. Okara is preferably a dried product, more preferably a powdered dried product.

In the present invention, "bran" means a skin (outer skin, germ, etc.) that is removed during wheat milling, and any form that can be blended with a resin can be used. The bran may be in the form of powder, for example.

The upper limit of the content (total amount) of the natural organic matter is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, based on the resin composition.

The lower limit of the content (total amount) of the natural organic matter is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, based on the resin composition.

[others]
Hereinafter, other components that may be contained in the resin composition of the present invention will be exemplified.

As a resin other than biodegradable resin,
Polyolefin-based resins such as polyethylene-based resins, polypropylene-based resins, polymethyl-1-pentene, ethylene-cyclic olefin copolymers;
Ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, metal salt of ethylene-methacrylic acid copolymer (ionomer), ethylene-acrylic acid alkyl ester copolymer, ethylene- Functional group-containing polyolefin resins such as methacrylic acid alkyl ester copolymers, maleic acid-modified polyethylene, and maleic acid-modified polypropylene;
Polyamide-based resins such as nylon-6, nylon-6,6, nylon-6,10, nylon-6,12;
Aromatic polyester resins such as polyethylene terephthalate and its copolymers, polyethylene naphthalate, and polybutylene terephthalate;
Polystyrene resins such as atactic polystyrene, syndiotactic polystyrene, acrylonitrile-styrene (AS) copolymer, acrylonitrile-butadiene-styrene (ABS) copolymer;
Polyvinyl chloride resin such as polyvinyl chloride and polyvinylidene chloride;
Polyphenylene sulfide;
Examples thereof include polyether resins such as polyethersulphon, polyetherketone, and polyetheretherketone.
However, from the viewpoint that the effect of the present invention is easily exhibited, the resin composition of the present invention does not contain a resin other than the biodegradable resin, or even if it contains a small amount (for example, 1.0 with respect to the resin composition). It is preferably mass% or less).

As the antistatic agent, for example, fatty acid diethanolamides such as lauryldiethanolamide and stearyldiethanolamide, and hydroxyl group-containing compounds such as alcohol amine compounds can be used. In particular, alcohol amines such as monoethanolamine, diethanolamine, triethanolamine and the like are preferable. Two or more antistatic agents can also be used in combination. These antistatic agents may be supported on calcium silicate, calcium carbonate, or the like. The range of carbon atoms of the acyl group of the fatty acid diethanolamide is preferably about 8 to 22 from the viewpoint that a sufficient antistatic effect can be exhibited.
The blending amount of such an antistatic agent is about 0.01 to 8.00% by mass, more preferably 0.02, when the total mass of the inorganic substance powder blended thermoplastic resin composition is 100% by mass. It is desirable that the mixture is blended in an amount of about 4.00% by mass, more preferably 0.05 to 3.00% by mass, and particularly about 0.10 to 1.50% by mass. By using the product within this range, a sufficient antistatic effect can be obtained, and there is little possibility that the resin surface becomes sticky or adversely affects the resin physical characteristics.

As the filler, either a synthetic product or a natural mineral-derived product can be used.
Examples of the filler include carbonates such as calcium, magnesium, aluminum, titanium, iron and zinc (excluding heavy calcium carbonate), sulfates, silicates, phosphates, borates, oxides, or these. The hydrate and the like can be mentioned.
More specifically, light calcium carbonate, magnesium carbonate, dolomite, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate. , Aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous soil, sericite, silas, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, graphite And so on.
However, from the viewpoint that the effect of the present invention can be easily exerted, the resin composition of the present invention does not contain a filler other than heavy calcium carbonate, or even if it contains a small amount (for example, 0. 1% by mass or less) is preferable.

As the colorant, any of conventionally known organic pigments, inorganic pigments or dyes can be used.
Examples of the organic pigment include azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindoleinone-based, geoosazine-based, perinone-based, quinophthalone-based, and perylene-based pigments.
Examples of the inorganic pigment include ultramarine, titanium oxide, titanium yellow, iron oxide (valve handle), chromium oxide, zinc oxide, carbon black and the like.

Examples of the lubricant include fatty acid-based lubricants (stearic acid, hydroxystearic acid, composite stearic acid, oleic acid, and their sodium, potassium, magnesium, calcium salts, etc.), aliphatic alcohol-based lubricants, and aliphatic amide-based lubricants. (Stear amide, oxystearo amide, oleyl amide, elsyl amide, ricinol amide, behen amide, methylol amide, methylene bisstearo amide, methylene bisstearo behen amide, higher fatty acid bisamide acid, complex type amide, etc.), aliphatic ester type Examples thereof include lubricants (-n-butyl stearate, methyl hydroxystearate, polyhydric alcohol fatty acid esters, saturated fatty acid esters, ester waxes, etc.), fatty acid metal soap-based lubricants, and the like.

Examples of the antioxidant include phosphorus-based antioxidants, phenol-based antioxidants, pentaerythritol-based antioxidants, and the like.

Examples of the flame retardant include halogen-based flame retardants, phosphorus-based flame retardants, non-phosphorus-based non-halogen flame retardants such as metal hydrates, and the like.

Examples of the effervescent agent include aliphatic hydrocarbons (propane, butane, pentane, hexane, heptane, etc.), alicyclic hydrocarbons (cyclobutane, cyclopentane, cyclohexane, etc.), halogenated hydrocarbons (chlorodifluoromethane, etc.). , Dichlorofluoromethane, trifluoromethane, trichlorofluoromethane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, chloromethane, chloroethane, dichlorotrifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichloro Examples thereof include tetrafluoroethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, perfluorocyclobutane, etc.), inorganic gases (carbon dioxide, nitrogen, air, etc.), water, and the like.

(Preferable composition of resin composition)
As a preferred embodiment of the resin composition of the present invention, for example, 55-65% by mass of PBAT and / or PBSA; 25-35% by mass of heavy calcium carbonate: epoxidized soybean oil, epoxidation with respect to the resin composition. 2.0 to 8.0% by mass, particularly 2.2% by mass or more 5 of epoxy compounds selected from linseed oil, epoxidized castor oil, epoxidized palm oil, bisphenol A type epoxy resin, and bisphenol F type epoxy resin. Less than 0.0% by mass; those containing 0 to 15% by mass of acetyltributyl citrate, particularly 5 to 10% by mass.

<Manufacturing method of resin composition>
The resin composition of the present invention can be produced by using the above-mentioned components based on a method conventionally known as a method for producing a resin composition.

The resin composition is obtained, for example, by mixing the components and melt-kneading.
The timing of mixing and melt-kneading can be appropriately set according to the molding method (extrusion molding, injection molding, vacuum forming, etc.) to be adopted. For example, the mixing may be performed before charging from the hopper of the molding machine or at the same time as molding.

The melt kneading may be performed by, for example, a twin-screw kneader, a kneader, a Banbury mixer, or the like. Further, the order in which each component is added to the kneader is not particularly limited, and the biodegradable resin, heavy calcium carbonate, and epoxy compound may be added at the same time, and two of these components are reserved. You may knead. It is also possible to produce a biodegradable resin composition kneaded with heavy calcium carbonate and a biodegradable resin composition kneaded with an epoxy compound by melt-kneading.

The form of the resin composition of the present invention can be, for example, pellets of any size and shape.

The shape of the pellet is not particularly limited, and may be, for example, a cylinder, a sphere, an elliptical sphere, or the like.

The size of the pellet is not particularly limited. For example, in the case of spherical pellets, the diameter can be 1-10 mm. In the case of an elliptical spherical pellet, the aspect ratio may be 0.1 to 1.0 and the length and width may be 1 to 10 mm. In the case of cylindrical pellets, it can be 1-10 mm in diameter and 1-10 mm in length.

A desired molded product can be obtained by molding the resin composition of the present invention after drying it, if necessary.

<Molded product>
The molded product of the present invention can be obtained by molding the resin composition of the present invention by any molding method.

The molded product of the present invention may have an arbitrary shape depending on the intended use and the like.
The molded product of the present invention is, for example, a film, a sheet, a container (food container, etc.), daily necessities (various disposable products, etc.), automobile parts, electrical and electronic parts, various consumables (in the field of building materials, etc.). And so on.

Since the resin composition of the present invention has good mechanical properties, it is particularly suitable for inflation molding or extrusion molding. Therefore, the molded article of the present invention is preferably an inflation molded article or an extruded article.

Examples of inflation molded products include films, sheets, and bags (plastic shopping bags, etc.).
The wall thickness of the inflation molded product is not particularly limited, but is preferably 10 μm to 200 μm, and more preferably 30 μm to 100 μm.

Examples of the extruded product include a film, a sheet, and a hollow product.

<Manufacturing method of molded products>
The method for producing a molded product of the present invention can be appropriately selected depending on the molded product to be obtained.
Examples of the method for manufacturing the molded product of the present invention include an inflation molding method, an extrusion molding method, an injection molding method, a foam injection molding method, an injection compression molding method, a blow molding method, a press molding method, a calendar molding method, and a vacuum molding method. And so on.

Molding conditions can be appropriately set according to the composition of the resin composition, the type of molded product, and the like.

When the molded product is a film, a sheet, or the like, it may or may not be stretched in the uniaxial or biaxial direction or the multiaxial direction at the time of molding or after molding.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Preparation of resin composition>
A resin composition containing each component shown in Tables 1 to 3 was prepared. The unit of the numerical value of the composition in the table is "part by mass".

The details of each component in the resin composition are as follows. Hereinafter, the "average particle size" is a value calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511 using the specific surface area measuring device "SS-100 type" manufactured by Shimadzu Corporation. Is.

(Biodegradable resin)
Biodegradable resin 1: Polybutylene adipate terephthalate 70% by mass and polylactic acid 30% by mass.
Biodegradable resin 2: Polybutylene succinate adipate 70% by mass and polylactic acid 30% by mass.
Biodegradable resin 3: Polybutylene adipate terephthalate 100% by mass

(Calcium carbonate)
CC1: Heavy calcium carbonate particles (average particle size: 2.2 μm, no surface treatment)
CC2: Heavy calcium carbonate particles (average particle size: 2.3 μm, surface-treated product with stearic acid)
CC3: Light calcium carbonate particles (average particle size: 1.5 μm, no surface treatment)

(Epoxy compound)
EP1: Epoxy soybean oil (molecular weight about 920, oxylan oxygen 6.7 to 7.0%, epoxy equivalent 228 to 239 g / eq)
EP2: Epoxy linseed oil (molecular weight about 950, oxylan oxygen ≧ 8.5%, epoxy equivalent ≦ 188 g / eq)
EP3: Bisphenol A type epoxy resin (epoxy equivalent 180-190 g / eq, liquid at room temperature)
EP4: Bisphenol F type epoxy resin (epoxy equivalent 160-180 g / eq, liquid at room temperature)
EP5: Bisphenol A type epoxy resin (epoxy equivalent 180-190 g / eq, liquid at room temperature, low chlorine type)

(Plasticizer)
Plasticizer 1: Glycerin fatty acid ester Plasticizer 2: Acetyltributyl citrate

(Antistatic agent)
HS15N: Antistatic agent containing lauryl diethanolamide and diethanolamine (manufactured by Kao Corporation)

(Natural organic matter)
CP: Cellulose powder with an average particle size of 20 μm

[Examples 1 to 4, Comparative Examples 1 to 4]
<Preparation of resin composition>
Each of the above raw materials was charged into the same-direction rotary twin-screw kneading extruder HK-25D (φ25 mm, L / D = 41) manufactured by Parker Corporation in the blending amount shown in Table 1 described later. This was extruded into strands at a cylinder temperature of 190 to 200 ° C., cooled and cut to prepare pellets of resin compositions having various compositions.

<Manufacturing inflation molded products>
A film was produced as an inflation molded product.
Specifically, the pellet was put into an inflation film extrusion line (60 mm circular die, 1.2 mm die gap, 30 mm screw diameter, L / D ratio = 30) to prepare a film having a thickness of 30 μm. The film was treated with a BUR (blow-up ratio) of 2.5.
In the extruder, the temperature of each area was set to 180 ° C to 200 ° C, and the rotation speed was maintained at 20 rpm.

<Evaluation of resin composition / film>
The obtained resin compositions and films were evaluated for moldability, tensile strength, elongation at cutting, and bleeding states by the following methods. The results are shown in Table 1 below.

(Formability)
Based on the state at the time of kneading / extrusion molding, the evaluation was made according to the following criteria. For some samples, the torque value of the extruder at the time of molding was measured and used as an evaluation material for moldability.
-◎: The kneading / extrusion operation proceeded extremely smoothly, and a film having a uniform thickness could be easily formed.
-○: It was possible to form a film having a uniform thickness without uneven distribution of the inorganic substance powder.
-Δ: Uneven distribution of the inorganic substance powder was observed, or it was difficult to form a uniform film.
-X: Extrusion molding was not possible due to a significant increase in viscosity during kneading.

(Tensile strength and elongation at cutting)
From each film, a dumbbell-shaped No. 3 test piece of JIS K6251: 2017 was obtained.
The tensile test of the obtained test piece was carried out at 23 ° C. using a strograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.). The stretching speed was set to 100 mm / min.
Based on the obtained stress-strain curve, the tensile strength (Ts, unit: MPa) and the elongation at cutting (EB, unit:%) were measured.

(Bleed)
The appearance of each film was visually observed and evaluated according to the following criteria.
-○: No bleeding was observed on the surface of the film.
-Δ: Slight bleeding occurred on the surface of the film.
・ ×: Bleed on the film surface was conspicuous.

(Biodegradable)
The size of each film was adjusted to 30 mm in length × 30 mm in width to obtain a test piece.
The obtained test piece was placed in a 25 ml vial with seawater (10 ml) whose temperature was adjusted to the same level as room temperature (25 ° C ± 5 ° C) and left for 1 month.
Then, the state of each test piece was visually observed and evaluated according to the following criteria.
A: The test piece is almost completely disassembled.
B: The test piece is partially disassembled, or no change is observed in the test piece.

According to the present invention, the resin compositions of Examples 1 to 4 containing a specific epoxy compound in an amount of 2.0% by mass or more and 8.0% by mass or less together with a biodegradable resin and heavy calcium carbonate have good processability. In addition, it gave a molded product with good mechanical properties, especially elongation at the time of cutting, and no bleeding was observed. Moreover, the biodegradability was not impaired by the compounding of the epoxy compound.

[Examples 5 to 10, Comparative Examples 5 to 6]
The same operation as in Example 1 was performed except that the types and blending amounts of the raw materials used were changed as shown in Table 2. The evaluation results of each sample are shown in Table 2.

According to the present invention, the resin compositions of Examples 5 to 10 containing a specific epoxy compound give a molded product having excellent moldability, good mechanical properties, and particularly excellent elongation at cutting, and bleeding is also observed at all. There wasn't. On the other hand, in the resin composition of Comparative Example 5 containing no epoxy compound, the moldability was low and the elongation at the time of cutting of the molded product was also small. Further, in the resin composition of Comparative Example 6 containing a general-purpose plasticizer, the moldability was good, but the mechanical properties of the molded product were low, and the bleeding of the plasticizer was conspicuous. The advantages of using certain epoxy compounds are obvious. Among them, the molded products of Examples 6 to 9 using EP2 to EP5 having an epoxy equivalent of 100 g / eq or more and 200 g / eq or less, and the molded product of Example 10 having an EP1 compounding amount of 3% by mass have mechanical properties. It was particularly good.

The same experiments as in Example 5 and Comparative Example 5 were carried out with the mass ratio of biodegradable resin: heavy calcium carbonate set to 90:10, but no significant improvement in elongation during cutting was observed by blending the epoxy compound. rice field. The improvement in mechanical properties in the resin composition of the present invention is not due to the plasticizing effect of the epoxy compound itself, but the decomposition product of the biodegradable resin component in the presence of heavy calcium carbonate reacts with the epoxy compound. It is suggested that it is brought about by doing.

[Examples 11 to 12, Comparative Example 7]
The types and blending amounts of the raw materials used were further changed as shown in Table 3, and the same operations as in Example 1 were carried out. The evaluation results of each sample are shown in Table 3.

According to the present invention, the resin composition of Example 11 further containing about 7% by mass of acetyltributyl citrate together with a biodegradable resin, heavy calcium carbonate, and a specific epoxy compound has extremely excellent moldability and mechanical properties. Gave a good molded product. Further, the molded product of Example 12 containing about 7% by mass of cellulose powder showed good mechanical properties.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a biodegradable resin-containing composition which gives a molded product having good molding processability, excellent mechanical properties, particularly excellent elongation at cutting, and less likely to cause deterioration of appearance due to bleeding. It became clear.

Claims (10)

A resin composition containing a biodegradable resin, heavy calcium carbonate, and an epoxy compound.
The mass ratio of the biodegradable resin to the heavy calcium carbonate is 10:90 to 50:50 .
The biodegradable resin comprises at least polybutylene adipate terephthalate or polybutylene succinate adipate.
The content of the polybutylene adipate terephthalate or the polybutylene succinate adipate is 70% by mass or more with respect to the biodegradable resin.
The content of the heavy calcium carbonate is 50% by mass or more with respect to 100% by mass of the resin composition.
The epoxy compound is one or more compounds selected from the group consisting of epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized palm oil, bisphenol A type epoxy resin, and bisphenol F type epoxy resin. can be,
The content of the epoxy compound is 2.0% by mass or more and less than 5.0 % by mass with respect to 100% by mass of the resin composition.
Resin composition. The resin composition according to claim 1, wherein the epoxy compound is a compound having an epoxy equivalent of 100 g / eq or more and 200 g / eq or less. The biodegradable resin comprises polybutylene adipate terephthalate and polylactic acid.
The mass ratio of the polybutylene adipate terephthalate to the polylactic acid is 70:30 to 90:10.
The resin composition according to claim 1 or 2 . The biodegradable resin comprises polybutylene succinate adipate and polylactic acid.
The mass ratio of the polybutylene succinate adipate to the polylactic acid is 70:30 to 90:10.
The resin composition according to claim 1 or 2 . Further containing 5% by mass or more and 30% by mass or less of natural organic substances with respect to 100% by mass of the resin composition.
The natural organic matter is one or more selected from the group consisting of cellulose powder, wood flour, starch, fir husks, okara, and bran.
The resin composition according to any one of claims 1 to 4 . The resin composition according to any one of claims 1 to 5 , wherein the average particle size of the heavy calcium carbonate by an air permeation method according to JIS M-8511 is 0.7 μm or more and 6.0 μm or less. The resin composition according to any one of claims 1 to 6 , further comprising acetyltributyl citrate in an amount of 5% by mass or more and 20% by mass or less with respect to 100% by mass of the resin composition. A molded product obtained from the resin composition according to any one of claims 1 to 7 . The molded product according to claim 8 , wherein the molded product is an inflation film. The molded product according to claim 8 , wherein the molded product is an extruded sheet.