KR970010841B1 - Biologically decomposable and disposable diaper - Google Patents

Abstract

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Description

Biodegradable disposable diapers

The present invention relates to a disposable diaper using a non-woven fabric of biodegradable polyester resin as a liquid permeable surface material and as an anti-leak lining material. More particularly, the present invention relates to disposable diapers which are not only turbid in terms of mechanical strength, flexibility, waterproofness, breathability and feel but also biodegradable premises.

Disposable diapers have recently been used for significantly extended applications and face various demands on quality.

In the construction of disposable diapers, various developments have been made. However, most disposable diapers are in contact with the user's skin and are generally referred to as cover stock, liquid permeable surfaces consisting of fluff pulp containing superabsorbent polymers and generally back sheets ( It consists of an anti-leak lining that prevents the leakage of water, called a bakc sheet.

Some older disposable diapers use paper. However, at present, nonwoven fabrics manufactured by thermal bond method or spun bond method are used in most disposable diapers.

On the other hand, as the anti-leak lining material, not only the excellent anti-wetting performance (water resistance), flexibility and moisture permeability of releasing the moisture inside, but also large crack or rupture strength are required. It is also required not to make a rumble sound.

Traditionally, anti-leak lining materials include plasticized polymer films such as polyvinyl chloride, low density polyethylene, polypropylene, polyurethane, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid ester copolymers, or the aforementioned films It is made of a film-like material formed by mixing and stretching a filler such as calcium carbonate to generate micropores and embossing the satin on the film.

Thus, in the known disposable diapers, the liquid-permeable surface material and the anti-leak lining material are not biodegradable, although the liquid absorbent material made of fluff pulp shows biodegradability. As a result, when the diaper is embedded in the ground, the surface material and the lining material remain undecomposed. Thus, for complete disassembly, it is necessary to incinerate the entire diaper or to separate the liquid permeable surface material and the leak-proof lining material from the top sheet layer for separation incineration.

SUMMARY OF THE INVENTION An object of the present invention is to develop a biodegradable disposable diaper which uses a biodegradable liquid permeable surface material and a biodegradable waterproofing lining material in combination and exhibits high productivity as well as superior mechanical strength, flexibility, feel and waterproofness. It is also an object of the present invention to develop a biodegradable disposable diaper with imparted breathability without deteriorating the waterproofness. It is also an object of the present invention to supply a diaper having an extremely good touch top sheet layer.

For this purpose, according to the present invention, there is provided a biodegradable disposable diaper composed of a combination of a liquid absorbent material, a liquid permeable surface material and a leak-proof lining material. The liquid permeable material and the leakproof material are formed of an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer which is a practical group with a coupling agent so that the terminal group is specifically specified. The waterproof lining material is made of nonwoven fabric to impart breathability to the diaper without impairing the waterproofness. Non-woven fabrics are also used as liquid-permeable surface materials and / or side portions of diapers and aliphatic saturated polys with coupling agents treated by dry, spunbond, thermal bond, stitch bond, or needle punch methods. It is formed of an ester. The nonwoven fabric is also made of aliphatic saturated polyester resin with or without a coupling agent using the melt blown method and used as a liquid permeable surface material or side portion of the diaper, thereby having an excellent touch Diapers are obtained.

Liquid absorbent materials used in the present invention should be biodegradable and can be used in traditional diapers, for example composed of superabsorbent polymers contained in fluff pulp.

Hereinafter, the content of the present invention will be described in detail.

The aliphatic polyester used as the liquid permeable surface material and the anti-leak lining material in the disposable diaper of the present invention, if necessary, contains two components of glycols and dicarboxylic acid (or acid anhydride thereof) as the third component, or The polyester obtained by reacting with 1 or more types of polyfunctional components selected from the group which consists of tetrafunctional valence alcohols, oxycarboxylic acids, and polyvalent basic carboxylic acids (or its acid anhydrides) is comprised as a main component. Aliphatic polyesters are produced by reacting a relatively high molecular weight polyester prepolymer having a hydroxyl group at its end with a coupling agent, and making them into a higher molecular weight polymer.

It is known to produce polyurethanes by reacting low molecular weight polyester prepolymers having a number average molecular weight of 2,000 to 2,500 with terminal groups in the production of rubbers, foams, paints and adhesives with diisocyanates as coupling agents.

However, these polyester prepolymers used in polyurethane foams, paints and adhesives are low molecular weight prepolymers having a maximum number average molecular weight of 2,000 to 2,5000 that can be produced by a non-catalytic reaction. In order to obtain practical properties such as polyurethane, the amount of diisocyanate should be as much as 10 to 20 parts by weight based on 100 parts by weight of such a low molecular weight prepolymer. When a large amount of diisocyanate is added to the low molecular weight polyester in this manner, gelation occurs and a resin capable of ordinary melt molding cannot be obtained.

Therefore, the polyester obtained by using a large amount of diisocyanate upon reaction with a low molecular weight polyester prepolymer as a raw material cannot be used as the plastic raw material for nonwoven fabric of the present invention.

Also, in the case of polyurethane rubber, although the method of devising a method of converting hydroxyl groups to isocyanate groups by adding diisocyanate and further increasing the number average molecular weight using glycol, the amount of diisocyanate used is described above. The same problem as described above occurs that 10 parts by weight or more are required with respect to 100 parts by weight of the prepolymer in order to obtain the practical properties of. When relatively high molecular weight polyester prepolymers are used, the heavy metal catalysts required in the preparation of the prepolymers promote the reactivity of the isocyanate groups described above, which undesirably leads to poor storage, crosslinking and branching and thus polyester prepolymers. When prepared without a catalyst, its number average molecular weight is limited to about 2,500.

The polyester prepolymer for obtaining the aliphatic polyester used in the present invention has a relatively high molecular weight of 5,000 or more, preferably 10,000 or more, and a relatively high molecular weight of saturated aliphatic having a melting point of 60 ° C. or more, having substantially hydroxyl groups at its ends. Polyester, which is obtained by reacting glycols with these basic carboxylic acids (or acid anhydrides thereof) in the presence of a catalyst. When a prepolymer having a number average molecular weight lower than 5,000 is used, a small amount of the coupling agent used in the present invention in a portion of 0.1 to 5 parts by weight cannot provide a polyester having good physical properties.

The polyester prepolymer having a number average molecular weight of 5,000 or more has a hydroxyl value of 30 or less, and a small amount of coupling agent does not affect the remaining catalyst even under difficult conditions such as molten state. Can be prepared.

Thus, the polymers used in the present invention are polyester prepolymers having a number average molecular weight of at least 5,000, preferably at least 10,000 and consisting of aliphatic glycols and aliphatic dicarboxylic acids, for example derived from diisocyanates as coupling agents. It has a chain structure that is combined through a urethane bond.

In addition, the aliphatic polyester used in the present invention is, for example, when the polyester prepolymer has a long chain branch derived from a polyfunctional component, for example, via a urethane bond derived from diisocyanate as a coupling agent. It has a combined chain structure. As the coupling agent, when oxazoline, epoxy compound and acid anhydride are used, the polyester prepolymer has a chain structure via an ester bond.

Until now, a biodegradable thermoplastic film or the like was used as the liquid permeable surface material and the waterproofing lining material for disposable diapers. As a result, despite the fact that the liquid absorbent material used in the diaper is biodegradable, the entire diaper is not biodegradable. As a result, such known diapers cannot be landfilled and can only be disposed of by incineration, which is a burden on the small-sized steel sheets and is undesirable.

Under these circumstances, the present invention uses an aliphatic saturated polyester resin obtained by reacting a saturated polyester prepolymer having a terminal group with a hydroxyl group and a coupling agent as a raw material for the liquid-permeable surface material and the anti-rust lining material, or Using the aliphatic saturated polyester resins described above and aliphatic saturated polyester resins not treated with a coupling agent, it has been successful to obtain disposable diapers wholly biodegradable.

In addition, by using a nonwoven fabric made by blending or laminating fabrics produced by the spunbond method or blown method from the polyester resin as such raw materials, it is possible to remarkably improve breathability without degrading biodegradability and waterproofness. Thus, it is successful in reducing molding due to wear of the diaper.

When the liquid permeable surface material and the anti-leak lining material made from the above-mentioned polyester resins are used together with the traditional liquid absorbent material, they are excellent not only in biodegradability, breathability and waterproofness, but also in mechanical strength, flexibility, and feel. We supply biodegradable disposable diapers with bonding and heat set properties that are manufactured with high productivity.

Glycols that can be used as the reaction component include aliphatic glycols. Among these, those having 2,4,6,8 and 10 even linear alkylene groups include, for example, ethylene glycol, 1,4-butanediol, 1,6-exodiol, 1,8-octanediol , 1,10-decanediol and mixtures thereof are preferred.

Among these glycols, those having a small number of carbons such as ethylene glycol, 1,4-butanediol and 1,6-hexanediol are preferable because they can produce high crystallinity and high melting point aliphatic polyester. In particular, ethylene glycol and 1,4-butanediol are most suitable because they give good results.

Examples of aliphatic dicarboxylic acids or anhydrides thereof that react with glycols to provide aliphatic polyesters include aliphatic dicarboxylic acids. Among these, as those having an even numbered straight alkylene group having 2,4,6,8 and 10 carbon atoms, for example, succinic acid, adipic acid, suberic acid, sebacic acid, 1,10-decanedicarboxylic acid , Succinic anhydride and mixtures thereof are preferred. Among these dicarboxylic acids, for example, those having low carbon numbers such as succinic acid, adipic acid and succinic anhydride are preferable because they can produce aliphatic polyesters having high crystallinity and high melting point. In particular, acid mixtures of succinic acid, succinic anhydride and succinic acid or succinic anhydride with other dicarboxylic acids such as adipic acid, suveric acid, sebacic acid or 1,10-decanedicarboxylic acid are preferred.

When the mixed acid contains, for example, two or more components of succinic acid and other dicarboxylic acids, the mixing ratio of succinic acid is 70 mol% or more, preferably 90 mol% or more, and the mixing ratio of other carboxylic acids is 30 mol% or less, Preferably it is 10 mol% or less.

The combination of 1,4-butanediol and succinic acid or succinic anhydride and the combination of ethylene glycol and succinic acid or succinic anhydride are particularly preferred in the present invention because they exhibit a melting point similar to that of polyethylene.

(Third component)

One or more polyfunctional components selected from the group consisting of trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polyvalent base carboxylic acids (or acid anhydrides thereof) as the third component, if necessary for such glycols and dicarboxylic acids. Can be added. The addition of this third component creates long chain branches, and as the molecular weight increases, the ratio of weight-average molecular weight (MW) / number-average molecular weight (Mn) increases with molecular weight, i.e., the molecular weight distribution is wide. It is possible to impart desirable moldability to the polymer before polyester.

As the amount of the polyfunctional component added without the risk of gelation, 0.1 to 5 mol% of the trifunctional component or 0.1 to 3 of the tetrafunctional component relative to 100 mol% of all the components of the aliphatic dicarboxylic acid (or its acid anhydride) Mol% is added.

(Multifunctional component)

Examples of the polyfunctional component as the third component include tri- or tetra-functional polyhydric alcohols, oxycarboxylic acids and polybasic capric acids.

Trifunctional polyhydric alcohols typically include trimethylol propane, glycerin or anhydrides thereof. The tetrafunctional polyhydric alcohols are typical of pentaerythritol.

The trifunctional oxycarboxylic acid component is divided into two types: (i) a component having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) another component having one carboxyl group and two hydroxyl groups in the same molecule. . Malic acid having two carboxyl groups and one hydroxyl group in one molecule is practically advantageous and sufficient for the purposes of the present invention in the sense that it must be available at low cost in order to be readily available on the market.

There are three types of tetrafunctional oxycarboxylic acid components.

(i) a component that shares three carboxyl groups and one hydroxyl group in the same molecule, (ii) another component that shares two carboxyl groups and two hydroxyl groups in the same molecule, and (iii) three hydroxyl groups Residual component in which one carboxyl group is shared in the same molecule. Although any kind can be used, citric acid and tartric acid are practically advantageous and sufficient for the purpose of the present invention in view of being readily available as a commercially available product at low cost.

As a trifunctional polyvalent base carboxylic acid (or its acid anhydride) component, trimesic acid, propane tricarboxylic acid, etc. are used. Among them, trimesic anhydride is practical for the purposes of the present invention.

As the tetrafunctional polyvalent base carboxylic acid (or a salt thereof), various aliphatic compounds, ring aliphatic compounds, aromatic compounds and the like described in the literature are used. From the standpoint of availability, which is easy for commercial use, for example, pyromellitic anhydride, benzophenone anhydride tetracarboxylic acid and cyclopentane terteracarboxylic anhydride are practical and sufficient for the purpose of the present invention.

Glycols and this basic acid are used as the main component of the aliphatic system and a small amount of other components such as an aromatic series. Since these other components destroy biodegradability, they can be mixed or copolymerized only in amounts of up to 20% by weight, preferably up to 10% by weight and more preferably up to 5% by weight.

The polyester prepolymer for aliphatic polyester used in the present invention has a hydroxyl group as a terminal group. In order to introduce a hydroxyl group, it is necessary to use a slight excess of glycol.

To produce relatively high molecular weight polyester prepolymers it is necessary to use a deglycol-reaction catalyst in the deglycol reaction following esterification.

Examples of the deglycol reaction catalyst include titanium compounds such as aceto acetoyl titanium complex compounds and organic alkoxy titanium compounds. These titanium compounds can be used in combination. Examples of compounds used in combination include diacetoacetoxy oxytitanium, (Nippon Chemical Industry Co., Ltd; Nursem Titanium) tetraethoxy titanium, tetrapropoxy titanium, tetrabutoxy titanium and the like. The amount of the titanium compound to be used is 0.001 to 1 parts by weight and preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the polyester prepolymer. Such titanium compounds may be mixed prior to esterification or mixed just prior to the deglycol reaction.

As a result, polyester prepolymers usually have a number average molecular weight of at least 5,000 and preferably at least 20,000 and a melting point of at least 60 ° C. and are generally readily obtained. It is more preferable if such polyester prepolymer has crystallinity.

A coupling agent may be added to a polyester prepolymer having a number average molecular weight of 5,000 or more, preferably 10,000 or more, and a terminal group of which is substantially a hydroxyl group, in order to increase its number average molecular weight.

When aliphatic polyester without coupling treatment is used, it is not essential that the end group is a hydroxyl group, and it is particularly required that the esterification is sufficiently performed. Therefore, a flow characteristic with a MFR (190 ° C.) of at least 300 to 1000 g / 10 min is required.

The coupling treatment causes a coupling agent to react with the polyester prepolymer to produce an aliphatic saturated polyester resin. As the coupling agent, diisocyanate, oxazoline, diepoxy compound or acid anhydride can be used. However, preference is given to using diisocyanates in view of the reactivity and the performance of polyesters made from coupling agents.

The type of diisocyanate is not particularly limited and includes the following types. A mixture of 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate 1,5-naphthylene diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate Isocyanate, hexamethylene diisocyanate, isopron diisocyanate and the like.

In particular, hexamethylene diisocyanate is preferable in view of the color of the resulting resin, the reactivity when the polyester is added, and the like.

When an oxazoline or diepoxy compound is used as the coupling agent, the introduction of the coupling agent must be carried out after the hydroxyl group of the prepolymer is reacted with acid martial arts so as to convert the hydroxyl group end to a carboxyl group.

The addition amount of the coupling agent depends on whether a film or nonwoven is used, and when the nonwoven is used, whether the nonwoven is formed by the spun bond method or the melt blown method. However, in general, the content of the coupling agent is in the range of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, relative to 100 parts by weight of the polyester prepolymer.

When the content of the coupling agent is 0.1 parts by weight or less, the coupling reaction does not sufficiently occur. On the other hand, gelling occurs remarkably when its content exceeds 5 parts by weight.

The addition is preferably carried out when the polyester is under easily stirrable conditions in a uniformly molten state. Although it is not impossible to add the coupling agent to the solid polyester prepolymer and melt-mix it through an extruder, it is added to the polyester manufacturing equipment or to the melted polyester prepolymer (eg, in the kneader). It is more practical to do.

When adopting the melt-blown method, it is preferable to use a coupled high fluidity resin. However, the treatment of the coupling agent can be omitted, especially when a resin having a low melt viscosity is used.

When the aliphatic polyester is used to obtain a disposable diaper according to the present invention, if necessary, not only antioxidants, heat stabilizers, ultraviolet absorbers and the like, but also lubricants, waxes, colorants and crystallization accelerators are used in combination. Of course.

That is, the antioxidant is sulfur such as screened phenolic antioxidants such as p-tert-butyl hydroxytoluene and p-tert-butyl hydroxyanisole, distearyl thiodipropionate and dilauryl thiodipropionate. Antioxidant; triphenyl phosphite, trilauring phosphite, tris-nonylphenyl phosphite, and the like; and, as the ultraviolet absorber, p-tert-butyl phenyl salicylate , 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyllophenone, and the like, and as a lubricant, Calcium stearate, zinc stearate, barium stearate, sodium palmitate, etc., and as an antistatic agent, N, N-bis (hydroxyethyl) alkyl amine, alkyl amine, alkyl allyl sulfonate, alkyl sulfonate, etc. The flame retardant includes hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, and the like. The inorganic fillers include calcium carbonate, silver silica, titanium oxide, Talc, mica, barium sulfate, alumina, and the like, and hardening accelerators include polyethylene, terephthalate, poly-trans-cyclohexanedimethanol detraphthalate, and the like.

The biodegradable polyester resin obtained by the above process method is formed into a nonwoven fabric, which is used as the liquid permeable surface material of the present invention. As the anti-rust lining material, a film or nonwoven fabric of biodegradable polyester can be used.

When biodegradable polyester is used in the form of a film, the film can be produced by an inflation method or a T-die methed, as in the case of conventional thermoplastic resins. In such a case, the film can be prepared by blending a filler such as calcium carbonate, extruding the film material in the form of a film, stretching the film and staining einboss processing, thereby producing other types of resin. An airtight lining material having high breathability is obtained as in. The thickness of the film is preferably in the range of about 20 to 50 μm, as in the case of the nonwoven fabric, so that the biodegradable lining material in the form of a film may have the same mechanical strength, flexibility, waterproofness, and breathability as that of the nonwoven material.

The breathability of the film with micropores formed by stretching the material containing the filler is still insufficient, and the molding occurs somewhat unavoidably. In view of this fact, the present invention also aims to develop not only biodegradable but also waterproof lining material with improved breathability without compromising waterproofness.

From the polyester resin formed by laminating fabrics produced by the spun bond method (generally, 0.3 to 10 d of fiber) or the melt blown method (generally, 0.01 to 1 d of fiber are obtained). It has been found that when nonwoven fabric is used as an anti-leather lining material, a permeable, breathable biodegradable disposable diaper can be obtained.

The polyester resin used for this invention can select the molecular weight of a polyester prepolymer or the compounding quantity of a coupling agent, and can easily change its melting characteristic. In addition, since the obtained fibers can be easily bonded by thermal bonding, the nonwoven fabric can be produced with maximum productivity using the spun bond method, the melt blown method, the step bond method and the needle punch method.

The nonwoven fabric of the anti-rust lining material is formed by overlapping 95 to 90% by weight of the fabric made by the spunbond method and 5 to 50% by weight of the fabric made by the melt blown method, or by fabricating the fiber produced by such a method in line. The use of non-woven fabrics made solely of fibers made by spun-bonding methods is undesirable because such nonwoven fabrics are highly breathable but inferior in water resistance, but are not preferred because they are made of melt-blown methods. Since the nonwoven fabric is excellent in waterproofness but inferior in strength, this kind of nonwoven fabric must have a thickness capable of supplying the required level of rigidity.

When blending spunbond fibers and melt blown fibers or laminating fabrics of such fibers to produce nonwovens, it is desirable to place the portion of the meltblown fibers on the inner side that is in contact with the user's body.

Room nuseong lining material is the room pressure 1000mmH ₂ O or more, moisture permeability 2500~6000g / · m ² and air permeability properties of 24 hours 200~l000sec / 100cc are preferred. This property can be easily revealed using a nonwoven fabric made by blending spunbond fibers and melt blown fibers. With the use of nonwovens it is possible to obtain high waterproof pressures comparable to films with a waterproof pressure of at least 2000 mmH ₂ O, while maintaining moisture permeability and breathability at high levels of 2500 to 6000 g / m ² and 700 to 900 sec / 100 cc. Therefore, it is possible to greatly reduce the lump and prevent the rash of the skin due to the wearing of the diaper.

On the other hand, when the fabric or nonwoven fabric prepared from the polyester resin is used as the material of the liquid permeable surface material, it is prepared by thermal bonding (nuclear wrapping method) or spun bond method from the polyester resin specified in the present invention. Fabrics or nonwovens are made from relatively thick fibers such as back.

Such woven or nonwoven fabrics exhibit high breathability and small absorbency, unlike pulp-based tissues or cotton, providing improved tactile feel.

Particularly high levels of water repellency are required in the side portions of the liquid permeable surface material. Preferably, nonwoven fabrics produced from the melt blown method and the spun bond method from the polyester resin are used as such side part materials. The use of nonwoven fabrics produced only by the melt blown method cannot provide sufficiently high strengths, whereas the use of nonwoven fabrics produced by the spunbond method has sufficient water repellency due to the huge fiber thickness, despite satisfactory high stiffness obtained. Can not provide effect. It is possible to produce both liquid permeable surface materials and anti-leak lining materials from the same polyester resin. In this case, since thermal bonding is easily performed, high productivity of the disposable diaper is advantageously obtained.

In the disposable diaper, it is of course preferable to make the polyester resin such as the waistband other than the fluff pulp or the elastomer in view of biodegradability.

According to the present invention, as a disposable diaper, a liquid permeable surface material made of a biodegradable polyester resin is used in combination with a biodegradable leakproof lining material. As a result, since the whole diaper is biodegradable, it is possible to completely solve the problem of environmental destruction even when disposed of in the soil.

In addition, the anti-leak lining material made of nonwoven fabric provides sufficient breathability without lowering the waterproofness, thereby reducing the cohesion of the diaper.

In addition, when the liquid-permeable surface material is manufactured into a woven or nonwoven fabric by thermal bonding (nucleating method) or spun bonding using the above biodegradable polyester resin, diapers can be manufactured with improved productivity by thermal bonding. .

Example

The methods of the present invention are described with reference to the following examples. However, the present invention is not limited only to this.

(Synthesis method of resin)

(Resin B1)

The 700 liter reaction vessel was replaced with nitrogen gas and 183 kg of 1,4-butanediol and 224 kg of succinic acid were injected therein. After raising the temperature under nitrogen stream, it is esterified by dehydration condensation at 192 to 220 ° C. for 3.5 hours, and further esterification is continued for 3.5 hours under a reduced pressure of 20 to 2 mmHg after stopping the nitrogen injection. The collected sample had an acid value of 9.2 mg / g, a number average molecular weight (Mn) of 5,160 and a weight average molecular weight (Mw) of 10,670. Subsequently, 34 g of tetraisopropoxycitane is added as a catalyst at atmospheric pressure under a stream of nitrogen. The deglycol reaction is carried out at a temperature of 215-220 ° C. under a reduced pressure of 15-0.2 mmHg for 5.5 hours. The collected sample has an average molecular weight (Mn) of 16,800 and a weight average molecular weight (Mw) of 43,600. The yield of the resulting polyester prepolymer (A1) is 339 kg excluding condensate.

5.42 kg of hexamethylene diisocyanate was added to a reactor containing 339 kg of polyester prepolymer (A1) to carry out the coupling reaction at 180 to 200 ° C. for 1 hour. The viscosity increases rapidly but no gelation occurs. Then, 1.70 kg of Irganox 1010 (Ciba-geigy) as an antioxidant and 1.70 kg of calcium stearate as a lubricant are added, and the mixture is further stirred for 30 minutes. Extruded with water using the resulting reaction product extruder, cut into cutters and pelletized. The yield of aliphatic polyester (B1) obtained after vacuum drying at 90 ° C. for 6 hours is 300 kg.

Obtained polyester (B1) was pale ivory white waxy crystal with melting point of 110 ° C., number average of molecular weight (Mn) 35,500, weight average molecular weight (Mw) of 170,000, and MFR (190 ° C.) of 1.0 g / 10 The viscosity in the 10% orthochlorophenol solution in minutes was 230p, and the melt viscosity was 1.5 × 10 ⁴ p at a cutting rate of 100 sec ⁻¹ at a temperature of 190 ° C. The average molecular weight is determined by Shodex GPC System-11 (Showa Denko, gel permeation chromatography) using HFIPA solution (concentration of 0.1% by weight) containing 5 mmol CF ₃ COONa as the medium. Assay curves are drawn using PMMA standard samples (Shodex Standard M-75, Showa Denko).

(Number B2)

The 700 liter reaction vessel is replaced with nitrogen gas and 200 kg of 1,4-butanediol, 250 kg of succinic acid and 2.8 kg of trimethylol propane are injected inside. After raising the temperature under a nitrogen stream, it is esterified by dehydration condensation at 192 to 220 ° C. for 3.5 hours, and after stopping the nitrogen injection, further esterification for 3.5 hours under a reduced pressure of 20 to 2 mmHg. The collected sample had an acid value of 2.5 mg / g, a number average molecular weight (Mn) of 8,660 and a weight average molecular weight (Mw) of 9,250. Subsequently, 37 g of tetraisopropoxy titanol catalyst is added at atmospheric pressure under a stream of nitrogen. The deglycol reaction was carried out at a temperature of 215-220 ° C. under a reduced pressure of 15-0.3 mmHg for 8.0 hours. The established sample has an average molecular weight (Mn) of 16,200 and a weight average molecular weight (Mw) of 67,900. The yield of the resulting polyester (A2) is 367 kg excluding 76 kg of condensate.

330 g of hexamethylene diisocyanate was added to a reactor containing 367 kg of polyester (A2) to carry out the coupling reaction at 170 to 185 ° C for 1 hour. The viscosity increases rapidly, but no gelation occurs. Then, 370 g of Irganox 1010 (Ciba-Geigy) as an antioxidant and 370 g of calcium stearate as a lubricant are added, and the mixture is further stirred for 30 minutes. The resulting reaction product extruder is favorably extruded into water, cut into cutters and pelletized. After vacuum drying at 90 ° C. for 6 hours, the yield of polyester (B2) obtained is 360 kg.

Obtained polyester (B2) was pale ivory white waxy crystal with melting point of 110 ° C, number average of 25,600 of molecular weight (Mn), weight average molecular weight (Mw) of 120,000, and MFR (190 ° C) of 18g / 10 And a melt viscosity of 4.0 × 10 ⁴ p at a cutting rate of 100 sec ⁻¹ and a temperature of 190 ° C. The average molecular weight is measured as above.

(Resin B3)

The 700 liter reaction vessel is replaced with nitrogen gas and 196 kg of 1,4-butanediol and 204 kg of succinic acid are injected therein. After raising the temperature under nitrogen stream, it is esterified by dehydration condensation for 5 hours at 192-220 ° C, and further esterification for 3.5 hours under a reduced pressure of 15-2 mmHg after stopping the nitrogen injection. The collected sample had an acid value of 8.5 mg / g, a number average molecular weight (Mn) of 5,200 and a weight average molecular weight (Mw) of 10.100. Subsequently, 30 g of detriisopropoxy titanol catalyst is added at atmospheric pressure under a stream of nitrogen. The temperature was raised to a deglycol reaction for 15 hours under a reduced pressure of 5 to 0.2 mmHg at a temperature of 215 to 220 캜. The collected samples had a number average molecular weight (Mn) of 23,300 and a weight average molecular weight (Mw) of 89,300 (Mw / Mn = 5.4). The yield of the resulting polyester prepolymer (A3) is 327 kg excluding condensate.

327 g of Irganox B225 (Ciba-geigy) as antioxidant and 327 g of calcium stearate as lubricant are added to a reactor containing 327 kg of polyester prepolymer (A3) cooled to 180 ° C., and the mixture is further stirred for 30 minutes. The resulting reaction product is extruded into water using an extruder, cut into pellets and pelletized. The yield of aliphatic polyester (B3) obtained after vacuum drying at 90 ° C. for 6 hours is 310 kg.

Obtained polyester (B3) is white solid crystal, melting | fusing point is 120 degreeC, number average is 23,100 molecular weight (Mn), weight average molecular weight (Mw) is 90,500, MFR (190 degreeC) is 500g / 10min, 10% rise The viscosity in the chlorophenol solution is 20p, and the melt viscosity is 100p at the cutting speed of 1-10sec ^-1 (Tochimeck, rotary ciscometer), temperature 190 °. The average molecular weight is measured as above.

(Resin B4)

The 700 liter reaction vessel is replaced with nitrogen gas and 222.5 kg of 1,4-butanediol and 277.5 kg of succinic acid are injected therein. After raising the temperature under nitrogen stream, it is esterified by dehydration condensation at 195-210 degreeC for 5.0 hours, stops nitrogen injection, and further esterifies for 3.5 hours again under reduced pressure of 15-5 mmHg. The collected sample had an acid value of 9.1 mg / g, a number average molecular weight (Mn) of 5,300, and a weight average molecular weight (Mw) of 11.200. Subsequently, 30 g of tetraisopropoxy titanol catalyst is added at atmospheric pressure under a stream of nitrogen. The temperature was raised and the deglycol reaction was carried out at a temperature of 215 to 220 ° C. for 7.5 hours under a reduced pressure of 5 to 0.2 mmHg. The collected sample has an average molecular weight (Mn) of 17,200 and a weight average molecular weight (Mw) of 58,700. The yield of the resulting polyester prepolymer (A4) is 415,5 kg excluding condensate.

To the reactor containing 415.5 kg of polyester prepolymer (A4) was added 52 g of phosphoric acid as an anti-oxidant, 416 g of Irganox 1010 (Ciba-geigy) as an antioxidant and 416 g of calcium stearate as a lubricant, adding the mixture for another 30 minutes. Stir. Extruded with water using the resulting reaction product extruder, cut into cutters and pelletized. The yield of aliphatic polyester (B4) obtained after vacuum drying at 90 ° C. for 6 hours is 410 kg.

Obtained polyester (B4) was white solid crystal, melting | fusing point was 120 degreeC, the number average was 26,700 molecular weight (Mn), the weight average molecular weight (Mw) was 98,000, MFR (190 degreeC) was 120g / 10min, and was cut | disconnected. Melt viscosity is 700p at speed 1-10sec- ¹ (Tochimeck, rotary viscometer), temperature 190 degreeC.

Pellets of such a resin are molded after drying for 2 to 4 hours at 100 to 120 ° C. using a dew point controlled hot air circulation dryer.

[Inflation Film]

Calcium carbonate was mixed into the resin (B1) and blow-up ratio 3.0, using a circular die with a lip gap of 1.2 mm and a radius of 300 mm with a 600 mm∮ extruder. The mixture is extruded at a fold, take-up rate of 135 m / min to give an inflation film of 30 μm thickness. And this film is satin-processed. The film exhibits a strength of 650 kg / cm 2 in the MD direction and 670 kg / cm 2 in the TD direction. Elongation of 660% is shown in the MD direction and 790% in the TD direction.

[Spun-bond / melt-blow nonwoven fabric]

A specific nonwoven forming apparatus capable of forming spunbond nonwovens and meltblown nonwovens in an in-line manufacturing process is used.

The spun bond method is carried out by extruding the resin (B2) with an extruder of 65 mm diameter having a 200-hole × 5-row die of 1000 mm butterfly. On the other hand, the melt blown method is carried out by extruding the resin C using a superheated steam of 2.5 kg / cm 2 G as a high-speed injection gas with a 40 mm∮ extruder having 1000 holes × 1 row die at 1 mm pitch.

The filaments released by the spun bond method are precipitated on a collect conveyor and thermally bonded together by a pairing operation of a thermal coupling device having a flat roll and a slice roll, thereby obtaining a spunbond nonwoven fabric. .

The spunbond / melt blow process is performed by spinning melt blown filaments that spew onto spunbond filament fabrics being transported by a collect conveyor, blending and depositing the fibers with the fabric, and then pressure bonding them with the same thermal bonding device. The SB-MB mixed nonwoven fabric is obtained by performing the following.

Thermal Bond Nonwovens

The resin (B2) was continuously extruded using a 40 mm diameter extruder with 0.6 mm∮hole 68 multi-filament nozzles, followed by drawing, drawing and cutting to a length of 52 mm to obtain staple fibers. The monofilament of this fiber has a size of 4.3 Danieler, a strength of 42 g / d and an elongation of 43%.

The thermal bond nonwoven is obtained by cutting and depositing the fibers with a cutter to form a pressure bonded fabric with a calender roll.

[Manufacture of diapers]

The high absorbent polymer is placed in fluff pulp and wrapped with absorbent paper to form a liquid absorbent portion. The film or nonwoven fabric is bonded back and forth with the liquid absorbing portion between them to produce a diaper.

Example 1

A spunbonded nonwoven fabric of resin (B1) having a weight of 20 g / m 2 and a thickness of 0.19 mm is used as the liquid permeable surface material. Fluff pulp containing high absorbent polymer is used as the liquid absorbent material. The 30 mm-thick inflation film of resin (B1) is used as an anti-rust lining material. Biodegradable disposable diapers are made using these materials. Table 1 shows the performance of the materials used.

The diaper absorbs 200 cc of artificial urea and is embedded in the soil. The entire diaper is completely corroded after three months.

Example 2

A thermal bond method nonwoven fabric of resin (B2) having a weight of 20 g / m 2 and a thickness of 0.19 mm is used as the liquid permeable surface material. The liquid absorbing material and the anti-leak lining material are made of the same material as used in Example 1. Table 1 shows the performance of the material.

The diaper is embedded in the soil in the same manner as in Example 1. The diaper dissolves completely after three months.

Example 3

The melt blown fabric of resin (B3) having a weight of 15 g / m 2 is superimposed with the thermal bond fabric of resin (B3) having a weight of 45 g / m 2. Both fabrics are pressure-bonded using emboss rolls to give a nonwoven fabric of weight 60 g / m 2 and thickness 0.5 mm. A disposable diaper was manufactured under the same conditions as in Example 2 except that this nonwoven fabric was used as the anti-leak lining material. The performance of this material is shown in Table 1.

This diaper is subjected to the same biodegradation test as that of Example 1. The diaper is totally corroded and disassembled after 3 will.

Example 4

The melt blown fabric of resin (B4) having a weight of 15 g / m 2 is mixed and deposited with the spunbond fabric of resin (B2) having a weight of 45 g / m 2. Both fabrics are pressure bonded to give a nonwoven fabric of weight 60 g / m 2. A disposable diaper was manufactured under the same conditions as in Example 1 except that this nonwoven fabric was used as the anti-rust lining material. The performance of this material is shown in Table 1.

This diaper is subjected to the same biodegradation test as in Example 1. The diaper completely corrodes and disintegrates after three months.

Example 5

The melt blown fabric of resin (B3) having a weight of 2 g / m 2 is mixed and deposited with the spunbond fabric of resin (B2) having a weight of 18 g / m 2. Pressure bonding of both fabrics yields a nonwoven fabric having a weight of 20 g / m 2. A disposable diaper was manufactured under the same conditions as in Example 1 except that this nonwoven fabric was used as the anti-rust lining material. The performance of the materials used is shown in Table 1.

This diaper is subjected to the same biodegradation test as that in Example 1. The diaper completely corrodes and disintegrates after three months.

TABLE 1

Claims (4)

A biodegradable disposable diaper which sequentially contains a liquid permeable surface material, a liquid absorbent material, and a water-proof lining material, wherein the liquid-permeable surface material is attached to the liquid-absorbing material, and the liquid-absorbing material is attached to the water-resistant lining material The liquid permeable surface material and the anti-leak lining material are formed of (1) an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer having a terminal group with a hydroxyl group with a coupling agent, or (2) Biodegradation characterized in that it is formed of an aliphatic polyester resin obtained by reacting (A) an aliphatic saturated polyester prepolymer having a terminal group with a hydroxyl group with a coupling agent and (B) an aliphatic saturated polyester resin not treated with the coupling agent. Disposable diapers. The biodegradable disposable diaper according to claim 1 wherein the anti-leak lining material made of aliphatic polyester resin is a nonwoven fabric. The biodegradable disposable diaper according to claim 2, wherein the anti-leak lining material made of aliphatic polyester resin is a nonwoven fabric made by interweaving or laminating fibers or fabrics produced by the spun-bond method and the melt-blown method. The nonwoven fabric according to any one of claims 1 to 3, wherein the nonwoven fabric is used as a liquid permeable surface material, and the nonwoven fabric is (1) spun-bonded or thermal-bonded using aliphatic saturated polyester treated with a coupling agent. Spun-bonded or thermally-formed using an aliphatic saturated polyester consisting of a nonwoven fabric formed or (2) a nonwoven fabric treated with (A) a coupling agent, or (2) a (A) coupling agent. A biodegradable disposable diaper composed of a nonwoven fabric formed by a bond method and a filament or nonwoven fabric formed by a melt-blown method using an aliphatic saturated polyester resin (B).