JPH11172091A - Biodegradable resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce moldings composed of a biodegradable resin retaining sufficient strength for practical purposes with good moldabillity. SOLUTION: Moldings are composed of a biodegradable resin having a polybutylene succinate based and/or polyethylene adipate based aliphatic polyester and a polylactic acid as the major components at a ratio of the polybutylene succinate based and/or polyethylene adipate based aliphatic polyester component being not less than 50 wt.% and having a structure in which the particles of the polylactic acid portion are dispersed in the aliphatic polyester. Suitably, the particle diameter of the polylactic acid portion is not greater than 9 μm. Such moldings can be used as the products of various fields by molding the composition to any desired shape and retain sufficiently high strength and accordingly, in particular can be advantageously applied to slide fasteners and face fasteners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article comprising a polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester having a biodegradable function and polylactic acid. In particular, it relates to a fastener molded product processed by injection molding and extrusion molding.

[0002]

2. Description of the Related Art Polybutylene succinate and polyethylene adipate, which are biodegradable resins, are one type of aliphatic polyester mainly synthesized chemically from glycol and aliphatic dicarboxylic acid. Its main chemical structural formula is represented by the following general formulas (1) and (2).

Embedded image Among these, as for polybutylene succinate, the biodegradable resin "Bionore" containing it as a main component is already on the market, and "TECHNICAL DATA SHEET, Decomposable Plastics (1996) "provides an overview, properties and structure.

On the other hand, polylactic acid is chemically synthesized using L-lactic acid as a monomer. Its main chemical structural formula is represented by the following general formula (3).

Embedded image As for polylactic acid, the biodegradable resin "Lacti", which is mainly composed of polylactic acid, has already been put on the market. "SHIMADZU LACT Repo" issued by Shimadzu Corporation, the manufacturer
rt-lactic acid-based biodegradable plastic No. 1 racty "
Describes its structure, properties and mechanical properties. These biodegradable resins are stable in air, such as wood and paper, but biodegrade in compost, wet soil, activated sludge, freshwater and seawater, and eventually to water and dioxide. Decomposed into carbon.

[0004] Conventionally used synthetic resin products are:
Its excellent properties of being lightweight, inexpensive and easy to process allow it to penetrate every part of our daily life and become an indispensable material in modern economic society. Fasteners are no exception, and resin fasteners using synthetic resins are utilized in various products by utilizing their features. However, if disposed after use, it is accumulated in the environment without being decomposed as it is, which may cause pollution problems such as destruction and pollution of the natural environment. On the other hand, although there are few practical examples,
As an alternative to the existing synthetic resin, a product using a biodegradable resin having a small impact on the environment has appeared.

[0005]

However, when the above-mentioned biodegradable resin is used as an actual product such as a fastener, there are many problems to be solved such as strength and moldability. However, at present, no biodegradable resin satisfying all these requirements has been put on the market. Accordingly, an object of the present invention is to develop a method for producing a biodegradable resin molded article which can impart sufficient strength to a biodegradable resin for use as a fastener or the like, and has improved moldability during production. Accordingly, it is an object of the present invention to provide a molded article made of a biodegradable resin which has practically sufficient mechanical properties.

[0006]

According to the present invention, there is provided a biodegradable resin comprising polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester and polylactic acid as main components. The molded article has a polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester component occupying a proportion of 50% by weight or more, and has a structure in which particles of a polylactic acid portion are dispersed in the aliphatic polyester. A biodegradable resin molded product is provided. Such a biodegradable resin molded article can be used as a product in various fields by molding it into a desired shape, but can be advantageously applied to a slide fastener and a hook-and-loop fastener, in particular, because it maintains a sufficiently high strength.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a biodegradable resin with strength enough to withstand use as a fastener or the like, and
In order to improve the moldability, which is important during production, two different types of biodegradable resin materials are combined and the disadvantages of each biodegradable resin are compensated to provide better performance than the physical properties of individual resin materials. It is trying to draw out. In addition,
In the category of conventional synthetic resins, this technique is a technique generally called a polymer blend, and its technical content is described in, for example, Saburo Akiyama et al.
See Publishing (1981). The present inventors conducted intensive research on the strength of the biodegradable resin, which is a problem in using the biodegradable resin for fasteners, and as a result, focused on the dispersed state of the biodegradable resin, and controlled them. By performing, the material strength can be greatly affected, and the particle size of the component corresponding to the dispersed phase of the biodegradable resin and the material strength are significantly related, and the particle size is equal to or less than a specific value. The inventors have found that the strength of the material is significantly increased by doing so, and have completed the present invention.

In the case of polymer materials, when two components are mixed, one usually forms a dispersed phase and the other forms a continuous phase. These are called sea-island structures and have a significant effect on the strength of the material. In this regard, the multi-component system of existing synthetic resins has been scrutinized, and edited by the Society of Polymer Science, Japan, “Polymer Alloys-Fundamentals and Applications”, Tokyo Kagaku Dojin (198).
This is also described in detail in 1). In fact, even in a biodegradable resin molded product composed of polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester (hereinafter, simply referred to as aliphatic polyester) and polylactic acid, one is a dispersed phase and the other is a dispersed phase. Will form a continuous phase. The physical properties of the molded article differ greatly depending on which of the two resins forms the dispersed phase. What determines this choice is the mixing ratio of the amphoteric resins.

Therefore, resins having various mixing ratios composed of polybutylene succinate / polylactic acid were prepared, and their physical properties were examined. The amount of elongation during the tensile test greatly depends on the dispersion state of both resins. It became clear that we were doing. FIG. 1 shows the elongation at the time of the tensile test for each mixing ratio. In FIG. 1, the abscissa indicates the percentage of polylactic acid in the mixed resin as a whole in% by weight, and the ordinate indicates the elongation in% Strain. The shaded area surrounded by the dotted line in the figure (the mixing ratio of polylactic acid is 10 to 45% by weight,% Strain
Is 200% or more) is the recommended range. Note that the distance between the marked lines at the time of elongation measurement was 50 mm.

From the results shown in FIG. 1, it is found that when the polybutylene succinate component is 50% by weight or more, the elongation becomes remarkably large.
At around 5 to 90% by weight, the% Strain exceeds 200%, indicating that this is the region with the largest elongation. The mixing ratio at which these elongations increase is a mixing ratio at which the polybutylene succinate component ratio is large, and it is easily expected that polybutylene succinate easily forms a continuous phase. In fact, when the dispersion state of the mixed resin having the mixing ratio within the above range is observed with an optical microscope, it can be understood that polylactic acid forms a dispersed phase and polybutylene succinate forms a continuous phase ( (Fig. 2). FIG. 2 shows that polybutylene succinate / polylactic acid = 50/50 mixing ratio (weight fraction)
2 shows a polarizing micrograph of a cross section of a monofilament. Imaging was performed using a quarter-wave plate under crossed Nicols conditions.
The matrix portion in the figure represents the polybutylene succinate component, and the mottled portion represents the polylactic acid component. The above results indicate that polylactic acid is a dispersed phase, and polybutylene succinate is a continuous phase, in other words, that the particles of the polylactic acid portion have a two-phase structure dispersed in a polybutylene succinate medium, It is shown that by setting the polybutylene succinate component to 50% by weight or more, preferably 55 to 90% by weight, a remarkable elongation can be imparted to the two-component resin product.

Therefore, in the present invention, in order to improve elongation occupying an important position in the mechanical properties of the material, based on the above-mentioned results, the biodegradable resin molded product is composed of two components of aliphatic polyester / polylactic acid. In the part where
An object of the present invention is to provide a biodegradable resin molded article having a two-phase structure in which particles of an aliphatic polyester component are 50% by weight or more and polylactic acid portions are dispersed in an aliphatic polyester medium. In order to produce such a biodegradable resin molded product, when mixing the aliphatic polyester and the polylactic acid, the amount of the aliphatic polyester to be mixed may be larger than that of the polylactic acid. That is, in the aliphatic polyester / polylactic acid two-component resin, in order to make the aliphatic polyester a continuous phase, the mixing ratio of the aliphatic polyester should be 50 to the total weight of the resin when mixing the biodegradable resin. % By weight or more. Since such a resin material exhibits high elongation as described above, a molded article can be manufactured with good moldability.

According to a study by the present inventors, a molded article characterized by the above conditions, that is, a two-phase structure in which particles of a polylactic acid portion are dispersed in an aliphatic polyester medium, It has been found that the particle size of the resulting polylactic acid particles greatly changes the strength of the material. In a polymer multi-component material, the size of the particles forming the dispersed phase greatly affects the strength of the material. The finer the particle size of the dispersed phase, the higher the strength of the material. In fact, for the two-component resin described above, when polybutylene succinate forms a continuous phase and polylactic acid forms a dispersed phase, the relationship between the particle size and material strength of the polylactic acid particles that are the dispersed phase should be determined by experiments. Is possible.
That is, in the two-component biodegradable resin, various samples having different particle sizes of the polylactic acid particles are prepared, the particle sizes of the polylactic acid are measured, the strength is obtained by a tensile test, and the relationship between the particle size and the strength is determined. I asked. The result is shown in FIG. In addition, the material mixing ratio of the prepared sample was polybutylene succinate /
Polylactic acid = 75/25 (% by weight).

As apparent from FIG. 3, when the polylactic acid particle size is 9 μm or less, a remarkable increase in the material strength is observed.
That is, in a preferred embodiment of the present invention, in a molded article having a two-phase structure in which particles of the polylactic acid portion are dispersed in an aliphatic polyester medium, the particle diameter of the polylactic acid portion is set to 9 μm or less, whereby The strength of the degradable resin molded product can be significantly improved. In order to improve the strength of the resin material, the smaller the particle size of the polylactic acid portion, the better. In the state where polybutylene succinate and polylactic acid are compatibilized, the polylactic acid particle diameter becomes the smallest,
The strength is also expected to be the highest. However, although compatibilization of both resins is theoretically possible, in practice,
In kneading, special equipment and technology are required, which is not practical in terms of cost. The present inventors have kneaded with ordinary kneading equipment and conditions so far, and as a result, the minimum polylactic acid particle diameter was 2 μm. Therefore, in the present invention, the particle size of the polylactic acid forming the dispersed phase is 2 μm
The above is considered preferable in a practical range.

As the biodegradable resin, polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester and polylactic acid used in the present invention, those produced by known methods can be used without any particular limitation. Further, the method for producing a molded article of the present invention is not limited to a specific method. To give an example of the most typical production method, first, an aliphatic polyester and a polylactic acid are kneaded using a kneading apparatus at about 190 ° C. at a weight ratio of a large amount of the aliphatic polyester. Next, the kneaded resin is molded by an injection molding machine, whereby the particles of the polylactic acid portion have a two-phase structure dispersed in an aliphatic polyester medium. Injection molded products can be obtained easily and with good reproducibility. The kneading temperature is not limited to the above-mentioned temperature, and may be kneaded at that temperature as long as it is equal to or higher than the melting temperature of the resin. As a method of kneading both resins, a method of not using a kneading apparatus, that is, a method of mixing both resins in a pellet state before molding can also be adopted.

The biodegradable resin molded article of the present invention can be applied to various fields, but since it has sufficiently high strength, it can be advantageously used for slide fasteners and hook-and-loop fasteners. Hereinafter, the application of the present invention to various fasteners will be specifically described with reference to the accompanying drawings. FIG.
Shows a slide fastener 1 used for opening and closing an opening of clothes or bags, for example, and has a product form in which upper and lower ends of a pair of left and right fastener stringers 2 are cut off. The fastener stringer 2 is composed of a biodegradable resin fastener tape 3 and a row of biodegradable resin elements (coil-shaped elements) 4 fixed to their facing edges. The fastener tape 3 is formed by weaving and / or knitting a biodegradable resin fiber, a nonwoven fabric, or a biodegradable resin sheet. As the element 4, an injection type in which individual elements are injection-molded and fastened to the edge of the fastener tape at the same time, a coil-shaped element in which a biodegradable resin monofilament is wound in a coil shape, and a horizontal direction in a plane. A continuous element such as a so-called zigzag element in which a portion bent in a U-shape is continuously formed in a zigzag shape along the longitudinal direction alternately up and down, and separated in parallel in the longitudinal direction by extrusion molding.
Various types of extruded elements, such as a ladder-shaped extruded element formed by connecting both ends of each element to a book connecting cord (core cord) and bending in a U-shape around a longitudinal center line. There is something. Further, for example, in the case of a coil-shaped element, a core string or a sewing thread is further added as a component. Reference numeral 5 is a slider for sliding and meshing / separating on opposing elements.

The slide fastener 1a shown in FIG. 5 has a form in which the upper end portion of each fastener stringer 2 is cut, and a lower stop portion 6 is formed by welding a predetermined lower portion of the row of the meshed elements 4. This is different from the slide fastener shown in FIG. On the other hand, a slide fastener 1b shown in FIG. 6 is an element 4 fixed to a fastener tape 3b of each fastener stringer 2b.
4 differs from the slide fastener shown in FIG. 4 in that an upper stopper 7 is fixed to the upper end of the row b and a lower stopper 8 is fixed to the lower end.

FIG. 7 shows an open type slide fastener 1c. An adhesive layer (not shown) is provided at the lower end of the fastener tape 3c of each fastener stringer 2c.
A reinforcing sheet-like member (taffeta) 9 is welded through the opening. A box 11 constituting a separable bottom end stop 10 is attached to one inner edge of the facing reinforcing sheet-like member 9, and a butterfly pin is attached to the inner edge of the other reinforcing sheet-like member 9. 17 are attached. The box body 11 is formed integrally with the guide projections 13 and the box rods 12 on the sides thereof, and a concave groove 14 is formed between the box rod 12 and the guide projections 13 so that the lower end of the slider 5 can slide. Have been. Similarly, the integrally formed butterfly pin 17 and the guide ridge 1 on its side are provided.
8, a guide groove 19 is also formed. Box 11
Is formed with a butterfly pin insertion hole 15 penetrating in the vertical direction in the left part of the hole.
6 are formed. Therefore, when inserting the butterfly pin 17 into the butterfly pin insertion hole 15 of the box 11, the inside of the lower end of the guide ridge 18 slides along the edge of the side groove 16 of the box 11, and guides the insertion of the butterfly pin 17. Therefore, the insertion operation can be performed smoothly. In FIG. 7, reference numeral 20 denotes a coil-shaped element 4c.
The reference numeral 21 denotes a sewing thread in which the core string 20 and the coil-shaped element 4c are sewn to the longitudinal edge of the fastener tape 3c.

As the separable bottom end stop, a so-called reverse open type is known, which can be disassembled or closed from the lower end of the slide fastener by forming a box having the same structure as that of the slider 5 into a box. It is not limited to the one shown in FIG. Furthermore, in the illustrated example, the reinforcing sheet-shaped member separate from the separable bottom end stop is described as being welded to the lower end portion of the fastener tape, but the sheet-shaped portion is formed of a biodegradable resin material into a box or a butterfly pin. Integrally molded with a reinforcing piece and a separable insert such as one that is integrally injection-molded and attached to the entire width of the fastener tape, or one that has a sheet-shaped part with a slit or the like with an arbitrary pattern to give flexibility. There was something
Not limited to a specific one.

According to the present invention, the above-mentioned fastener tape, element, slider, upper and lower stopper, sewing thread, core string,
All of the separable bottom end stop and the sheet-like member for reinforcement can be made from the above-described biodegradable resin of the present invention, or some members are made from other biodegradable resins or synthetic resins. You can also. When manufacturing a resin slide fastener, a suitable resin material depends on the product form of the slide fastener and the structure of each component. Depending on the required function and structure, for example, the slider itself may need to be made of another resin or metal. In such a case, the slider can be made of a required material. In addition, the present invention can be applied not only to the slide fastener of the type described above but also to other types such as a rail fastener.

A surface fastener made of a biodegradable resin is required to have a sufficient engaging force and durability even after repeated use to some extent from the viewpoint of its function. The engaging element of the hook-and-loop fastener is small or thin, so that biodegradation by microorganisms proceeds relatively smoothly, but biodegradation hardly proceeds because the base has a certain thickness. If the base is made thinner, biodegradation by microorganisms will easily proceed, but on the other hand, durability and strength will decrease.
Therefore, in a preferred embodiment, at least the base of the hook-and-loop fastener has a cross-sectional shape that increases its specific surface area. For example, a groove and / or a hole is formed in at least the base, or the inside of the engaging element is formed from the back of the base. To form a hole extending to. In addition, the hole here means
It should be understood as a concept including both aspects of a through hole and a non-through hole (or concave portion). In the flat base,
Making the surface rough is also an effective means.
As described above, by increasing the specific surface area of the base of the hook-and-loop fastener, the decomposition of the base by the action of microorganisms can be rapidly progressed while ensuring sufficient durability and strength. In addition, by forming the groove and / or the hole in the base, flexibility can be given to the base. Therefore, the engagement between the engagement elements can be quickly performed by the deformation of the base, and an improvement in the engagement force can be expected. .

The manufacture of the hook-and-loop fastener of the present invention can be carried out by various conventionally known methods except that the material used is a biodegradable resin, and the form is also limited to a specific one. is not. For example, as the male member, engaging elements of various shapes such as an engaging element having a hook shape, an engaging element having a semi-spherical head, and an engaging element having a conical head project from the base. Fasteners formed integrally from biodegradable resin and hook-and-loop fasteners formed by cutting loops protruding from a base fabric made of woven or knitted biodegradable resin fibers Can also be used, and also as a female member, a thing woven and knitted in a pile shape so as to form a loop from biodegradable resin fibers, a thing formed with a large number of loops on the surface by raising a woven or knitted fabric, or a nonwoven fabric As long as the engaging element of the male member can be engaged, all can be used. Furthermore, the head of the engaging element is shaped such that the hooks protrude in both directions or in multiple directions, so that these hooks engage with each other, thereby simultaneously functioning as a male member and a female member. The hook-and-loop fastener configured to perform the above-described process may be used.

Hereinafter, various embodiments of the biodegradable resin surface fastener of the present invention will be specifically described with reference to the drawings. 8 and 9 show a first embodiment of a surface fastener made of a biodegradable resin of the present invention. FIG. 8 is a perspective view of a male fastener 30 and FIG. 9 is a view of a male fastener 30 and a female fastener 40. The state of engagement is shown. Male surface fastener 3
Reference numeral 0 denotes a base 31 and a plurality of hook-shaped engaging elements 32 projecting from the base, which are integrally formed from the biodegradable resin as described above. It is formed so as to straddle the reinforcing ribs 33 arranged at predetermined intervals in the longitudinal direction. Also, on the back surface of the base 31,
Grooves (longitudinal grooves) 34 extending in the longitudinal direction are formed so that decomposition by the action of microorganisms can proceed promptly and maintain appropriate flexibility and strength. A vertical rib 35 is formed between them. The male surface fastener 30 includes a female surface fastener 40 in which a large number of loop-shaped engaging elements 42 are provided on the surface of a base 41 woven or knitted from biodegradable resin fibers, as shown in FIG. The hook-shaped engaging element 32 is
2 is engaged by being hooked.

FIGS. 10 and 11 show a second embodiment of the surface fastener made of a biodegradable resin according to the present invention. FIG. 10 is a perspective view of the male surface fastener 30a, and FIG.
a shows the engagement state between the female surface fastener 40 and a. The male surface fastener 30a of this embodiment has a pair of adjacent hook pieces 36, 37 whose hook-shaped tips are opposite to each other as engaging elements.
That the engaging element 32a is formed on the base 31a, the reinforcing rib 33a is formed only at the base end of each engaging element 32a, and that the bending in the lateral direction is ensured. Groove on the back side of the base 31a (horizontal groove)
The third embodiment is different from the first embodiment in that the first embodiment 34a is formed. The configuration of the female surface fastener 40 is the same as that of the first embodiment. The male fastener made of a biodegradable resin as described above is disclosed, for example, in US Pat.
No. 83, Japanese Patent Application Laid-Open No. 6-38811, by making a suitable design change (for example, adding a groove forming protrusion to a die, adding a groove forming roll, etc.). Can be.

FIGS. 12 and 13 show a third embodiment of the biodegradable resin surface fastener according to the present invention, which shows a piece-shaped surface fastener 30b of the same type for both sexes. The hook-and-loop fastener 30b is the same as the previous embodiment in that a base 31b and a large number of engaging elements 32b are integrally formed from a biodegradable resin, but a pair of engaging elements 32b projecting from both sides in an arc shape. A plurality of longitudinal grooves 34b are formed on the upper surface of the base 31b at the joint of the engaging elements 32b, and the engaging elements 32b of the grooves 34b are formed. The difference is that holes 38b are formed on both sides. By forming such a groove 34b and a hole 38b in the base 31b of the hook-and-loop fastener 30b, the action of decomposing by microorganisms can be accelerated, and the hook-and-loop fastener can be given appropriate flexibility and strength. The hook-and-loop fastener 30b has a pair of hook pieces 36b projecting to both sides,
37b and a large number of engagement elements 32b
By overlapping the two engaging elements so that they face each other, the hook piece of one hook and loop fastener can be engaged with the hook piece of the other hook and loop fastener. In the case of the hook-and-loop fastener 30b of the present embodiment, it can be formed by injecting biodegradable resin into the cavities of the upper mold and the lower mold having cavity surfaces of a predetermined shape. Also, unlike the embodiment described above,
Since it is molded into a piece (one piece) having a predetermined area, a large number of surface fasteners 30b are arranged and used adjacent to each other when used in a large area.

FIGS. 14 and 15 show a fourth embodiment of the male surface fastener made of a biodegradable resin according to the present invention. A monofilament or a multifilament is made of a biodegradable resin, and the surface is woven. The fastener is shown. In the female surface fastener 40a shown in FIG. 14, a pile (base cloth) 4 made of a biodegradable resin filament is similarly plain-woven from the biodegradable resin filament.
A female engaging element 4 woven into a pile in a
2a is formed to protrude from the base surface. On the other hand, the male surface fastener 30c shown in FIG. 15 has a structure similar to that of the female surface fastener, except that a part of the loop is cut to form the hook-shaped engagement element 32c.
The hook-and-loop fastener shown in FIG. 15 can be used as a hook-and-loop fastener of the same gender. A back coat 45 of a water-soluble resin or a biodegradable resin is applied to the back surfaces of the female fastener 40a and the male fastener 30c to prevent fraying. In addition, this back coat 4
By using a water-soluble resin for 5, the back coat 45 functions as an adhesive layer when moistened with water. In addition, even if such hook-and-loop fasteners 30c and 40a are discarded, a portion (3) made of a biodegradable resin is used.
1c, 32c, 41a, and 42a) are decomposed by the action of microorganisms, and the portion of the back coat 45 made of a water-soluble resin is dissolved and lost by rainwater or the like. Does not occur.
In addition, since the back coat 45 of the water-soluble resin dissolves and disappears, the bases (base cloths) 31c and 41a become woven cloth of biodegradable resin filaments having a large number of voids, so that the decomposing action by microorganisms is promptly performed. proceed.

FIGS. 16 and 17 show a fifth embodiment of the biodegradable resin surface fastener according to the present invention, in which a hole and a groove are formed in the base of the surface fastener by elution of a water-soluble resin into a solvent. An example is shown. The shape of the engaging element 32d of the male surface fastener 30d is the same as that of the embodiment shown in FIG. In this case, male surface fastener 30d
A part of the engaging element 32d and a part of the base 31d are made of a biodegradable resin, and a part to be a hole and a groove of the base is made of a
After being molded by the method described in FIG. 6, this is immersed in a solvent such as water or an aqueous alcohol solution to elute the water-soluble resin 46, thereby forming a male member having a hole 38d and a groove 34d formed in the base 31d as shown in FIG. The surface fastener 30d is obtained. As shown in FIG. 16, the male surface fastener 30d in a state where the water-soluble resin 46 is laminated on the back surface of the base 31d can be used as it is. In this case, the water-soluble resin 4
6 functions as an adhesive layer by moistening it with water.
Further, even if such male fasteners 30d are discarded, the water-soluble resin 46 is dissolved and disappears by rainwater or the like, and thereby the male fasteners 30d made of biodegradable resin are used.
Since the hole 38d and the groove 34d are formed in the, the decomposing action by microorganisms also proceeds rapidly. The male surface fastener 30d as shown in FIG. 16 is formed by forming a water-soluble resin film in which convex portions corresponding to holes and grooves are formed in advance from a biodegradable resin in a semi-molten male fastener. It can also be formed by press-fitting to the back surface of.

FIG. 18 shows a sixth embodiment of the male fastener made of biodegradable resin of the present invention. The male fastener 30e of this embodiment includes an engagement element 32 from the base 31e.
It has a hole 38e extending toward the point e, and has higher flexibility and a higher decomposition rate by microorganisms. Such a hole 38e is formed, for example, by forming a sharp projection corresponding to the shape of the hole 38e on the male surface fastener 30e in a semi-molten state or a softened state immediately after molding. It can be performed by pressing and laminating the resin film so that the protrusions are embedded therein, and then cooling and solidifying the male surface fastener, and then eluting the water-soluble resin film into an appropriate solvent. .
Further, as another example of the method of forming the holes and / or grooves as described above, a water-soluble resin film in which protrusions and / or protrusions corresponding to the holes and / or grooves are formed in advance in a lower mold is used. A method in which a surface fastener is formed from a biodegradable resin by disposing the film in a cavity and using the water-soluble resin film as a cavity surface of a lower mold can also be adopted.

The water-soluble resin used for forming the grooves and / or holes or as an adhesive layer is a water-soluble resin having a hydrophilic group such as a hydroxyl group, a carboxyl group, a sulfone group, and has moldability. Any material can be used, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, polyethylene oxide, C
MC, gum, etc., among which modified polyvinyl alcohol (e.g., Nippon Synthetic Chemical Industry Co., Ltd.'s Ecomaty AX (polyoxyalkylene grafted onto vinyl alcohol-allyl alcohol copolymer) is preferably used) Can be.

Other biodegradable resins that can be used in combination with the biodegradable resin according to the present invention, if necessary, have moldability, moderate flexibility and hardness, and are affected by the action of microorganisms. Any resin that can be disintegrated can be used. For example, a microbial fermentation-producing resin such as Biopol (a copolymer of hydroxybutyric acid and hydroxyvaleric acid) manufactured by Zeneca Corp. Natural polymers (starch) such as a blend of starch and modified polyvinyl alcohol), Novon (a blend of starch and a biodegradable synthetic polymer) manufactured by Warner Lumbard, USA
And synthetic resins such as Plaxel (polycaprolactone) manufactured by Daicel Chemical Industries, Ltd., and the like.

[0030]

EXAMPLES Examples of the effects of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1 A commercially available biodegradable resin was used as a raw material. In this example, "Bionore"# 1020 which is an aliphatic polyester-based biodegradable resin manufactured by Showa Polymer Co., Ltd. was used as polybutylene succinate, and polylactic acid manufactured by Shimadzu Corporation was used as polylactic acid. "Lacty" which is a biodegradable resin was used. First, these pellets were dried at 80 ° C. under reduced pressure for 4 hours. Both resins were weighed such that the ratio by weight was Bionole / Lacty = 75/25, and were charged into a kneading apparatus. After kneading at a kneading temperature of 170 ° C., a mixer rotation speed of 60 r / min and a kneading time of 5 minutes,
A resin a shown in Table 1 was obtained. The resin b was kneaded at a kneading temperature of 190 ° C., a mixer rotation speed of 60 r / min and a kneading time of 5 minutes, and the resin c was further kneaded at a kneading temperature of 210 ° C., a mixer rotation speed of 60 r / min and a kneading time of 5 minutes. Obtained.

Each of the resins a to c prepared by the above-described method was extruded into a monofilament, and the tensile strength was measured by a tensile tester. Further, the cross section of each monofilament made of resin a, b or c was observed, and the particle size of lacty, which is a polylactic acid component, was measured. Table 1 also shows the tensile strength and the particle size of lacty particles for each case. As can be easily seen from the results shown in Table 1, the particle size of the lacty particles in each resin is 9 μm or less, and the smaller the particle size, the higher the strength of the kneaded resin.

Further, for each of the resins a, b and c, an injection fastener of 5 VS standard was molded by an injection molding machine to obtain each fastener molded product A, B and C. For each of the molded products A, B and C, the transverse pull strength was measured. The results are shown in Table 1 together with the particle size of the lacty particles.
The transverse pulling strength was measured as shown in FIG. That is, the fastener chain 2d in which the engagement teeth 4d are engaged.
19, the tensile resistance of the fastener tape 3d is measured using a tensile tester at a constant speed (300 mm / min) in the chain meshing direction as shown in FIG. Note that the width of the clamp 50 is 25 mm. From the results shown in Table 1, it can be seen that the smaller the lacty particles, the higher the transverse pull strength of the fastener. In addition, in any case, 25 kg specified in the JIS standard of 5VS
The value exceeded the transverse pulling strength of f / 25 mm, and the effect of increasing the strength due to the particle size of the lacty particles being 9 μm or less was confirmed.

[Table 1]

[0034]

As described above, according to the present invention, the polylactic acid portion particles have a structure in which the polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester is dispersed, and are practically sufficient. A biodegradable resin molded product having high strength is provided and can be used as a product in various fields such as a slide fastener and a hook-and-loop fastener.
Moreover, such a biodegradable resin molded product can be manufactured with good moldability. In addition, the biodegradable resin molded article of the present invention is decomposed by microorganisms in the soil and water even when discarded, and thus does not cause destruction of the global environment or waste pollution. Moreover, products made of biodegradable resin are converted into compost and returned to the earth, so there is no danger of harm to wildlife due to scattered garbage like ordinary plastic products. It also helps to extend the life of the landfill and stabilize it. Furthermore, even if these products are incinerated, the risk of damaging the incinerator is reduced because the biodegradable resin generates less heat when incinerated. Furthermore, the biodegradable surface fastener to which the present invention is applied is suitably used as a connecting tool for various disposable products such as a binding band and a seedling cover, a enoki mushroom raising seedling cover, and a diaper that are made of, for example, a biodegradable resin or a water-soluble resin. be able to.

[Brief description of the drawings]

FIG. 1 is a graph showing the elongation of a resin having various mixing ratios of polybutylene succinate / polylactic acid during a tensile test.

FIG. 2: Polybutylene succinate / polylactic acid = 50 /
It is a polarization microscope photograph which shows the cross-section structure of the monofilament of the resin of 50 mixing ratios (weight fraction).

FIG. 3 is a graph showing the relationship between the tensile strength of polybutylene succinate / polylactic acid resin and the particle size of polylactic acid.

FIG. 4 is a plan view showing one embodiment of a slide fastener made of a biodegradable resin.

FIG. 5 is a plan view showing another embodiment of a slide fastener made of a biodegradable resin.

FIG. 6 is a plan view showing still another embodiment of the slide fastener made of a biodegradable resin.

FIG. 7 is a partially broken plan view showing another embodiment of a slide fastener made of a biodegradable resin.

FIG. 8 is a partial perspective view of the first embodiment of the male surface fastener made of biodegradable resin.

9 is a partial cross-sectional view showing an engaged state of the male fastener made of biodegradable resin and the female fastener made of biodegradable resin shown in FIG. 8, wherein the male fastener is viewed from the line AA of FIG. 2 shows a cross section in the direction.

FIG. 10 is a partial perspective view of a second embodiment of the male surface fastener made of biodegradable resin.

FIG. 11 is a partial cross-sectional view showing an engaged state between the male fastener made of biodegradable resin and the female fastener made of biodegradable resin shown in FIG. 10, wherein the male fastener is viewed from the line BB in FIG. 2 shows a cross section in the direction.

FIG. 12 is a perspective view of a third embodiment of the surface fastener made of biodegradable resin.

FIG. 13 is a partially broken side view showing a method of engaging the biodegradable resin surface fastener shown in FIG.

FIG. 14 is a partial cross-sectional view of a female surface fastener made of a biodegradable resin according to a fourth embodiment.

FIG. 15 is a partial sectional view of a male fastener made of a biodegradable resin according to a fourth embodiment.

FIG. 16 is a partial sectional view showing a state in which a water-soluble resin is laminated on the back surface of the base of the fifth embodiment of the male surface fastener made of a biodegradable resin.

FIG. 17 is a partial sectional view showing a fifth embodiment of the male surface fastener made of biodegradable resin.

FIG. 18 is a partial sectional view of a sixth embodiment of the male surface fastener made of biodegradable resin.

FIG. 19 is a schematic diagram showing a method for measuring the horizontal pulling strength in Example 1.

[Explanation of symbols]

1, 1a, 1b, 1c Slide fastener 2, 2b, 2c, 2d Fastener chain 3, 3b, 3c, 3d Fastener tape 4, 4b, 4c, 4d Element 5 Slider 6 Lower stop 7 Upper stop 8 Lower stop 9 Reinforcement sheet-like member 10 Separable bottom end fitting 30, 30a, 30b, 30c, 30d, 30e Male surface fastener 31, 31a, 31b, 31c, 31d, 31e, 4
1, 41a Base 32, 32a, 32b, 32c, 32d, 32e Hook-shaped engaging element 34, 34a, 34b, 34d Groove 38b, 38d, 38e Hole 40, 40a Female surface fastener

Claims (5)

[Claims] 1. A biodegradable resin molded product containing polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester and polylactic acid as a main component, wherein the polybutylene succinate-based and / or polyethylene adipate-based fat is provided. A biodegradable resin molded product, wherein the proportion of the aliphatic polyester component is 50% by weight or more, and the polylactic acid portion has a structure in which particles of the polylactic acid portion are dispersed in the aliphatic polyester. 2. The molded article according to claim 1, wherein the proportion of the polybutylene succinate-based and / or polyethylene adipate-based aliphatic polyester component is 55 to 90% by weight. 3. The molded article according to claim 1, wherein the particle size of the polylactic acid portion is 9 μm or less. 4. The molded article according to claim 1, wherein the molded article is a slide fastener. 5. The molded article according to claim 1, wherein the molded article is a surface fastener.