JPH06285112A - Biologically decomposable disposable diaper - Google Patents

Abstract

PURPOSE:To provide a disposable diaper which is biologically decomposable by combining the conventional fluff pulp, the liquid absorpive member made of highly water absorptive polymer, liquid-permeable surface member which possesses the mechanical strength, softness, skin touch feeling, waterproofness, and air permeability and is biologically decomposable, and the leak preventing back member. CONSTITUTION:A disposable diaper is formed by braiding the liquid-permeable surface member and the leak preventing back member which are made of a nonwoven fabric which consists of a liquid absorptive member being biologically decomposable and the polyester resin which is obtained by reacting the coupling agents with the saturated polyester prepolymer having the hydroxyl group as terminal group substatially or the aliphatic saturated polyester resin which is not coupling-treated with the above-described polyester resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disposable diaper using a non-woven fabric made of a biodegradable polyester resin as a liquid-permeable surface material and a leak-proof backing material, and having sufficient mechanical strength, flexibility and waterproofness. The present invention relates to a disposable diaper that is not only excellent in breathability and skin feel, but is biodegradable throughout the diaper.

[0002]

2. Description of the Related Art Disposable diapers have been remarkably widespread in recent years, and their quality requirements are becoming more and more diverse.

The constitution of these disposable diapers has been variously improved with the passage of time, but most of them are fluff pulp containing a liquid-permeable surface portion generally called a cover stock on the surface in contact with the skin and a highly absorbent polymer. And a leak-proof backing portion for preventing water leakage, which is generally called a back sheet.

Of these, the liquid permeable surface material used to be made of paper in the past, but nowadays most of them are non-woven fabrics made by a thermoplastic resin thermal bond method, a spun bond method or the like.

The leakproof backing material has leakproofness (waterproofness), flexibility and moisture permeability that allows moisture inside the diaper to escape to the outside, so that it feels good on the skin, is hard to tear, and has a rugged sound. What is not required is required.

Conventionally, polyvinyl chloride, low density polyethylene, polypropylene, polyurethane, ethylene-vinyl acetate copolymer, which has been plasticized as a material for a leakproof backing material,
A film such as an ethylene- (meth) acrylic acid ester copolymer or a film in which a filler such as calcium carbonate is mixed and stretched and micropores are generated, which is subjected to a satin embossing is mainly used. .

Therefore, although the liquid absorbent material made of fluff pulp is biodegradable, the liquid permeable surface material and the leakproof backing material are not biodegradable, and therefore, when disposed of in the soil. However, these materials do not rot and remain as they are. When this complete treatment was desired, it was necessary to incinerate the whole or separately treat the topsheet layer without the liquid-permeable surface material and the leakproof backing material.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a biodegradable liquid-permeable surface material and a leak-proof backing material which are excellent in mechanical strength, flexibility, feel to the skin, waterproof, and have good productivity. The purpose is to develop a combined biodegradable disposable diaper, further development of a biodegradable disposable diaper, which is provided with breathability without lowering waterproofness of the diaper,
In addition, the purpose is to develop a diaper having a topsheet layer that is extremely comfortable to the skin.

[0009]

The present invention provides a liquid-absorbent material and an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer having a terminal hydroxyl group with a coupling agent. By developing a biodegradable disposable diaper characterized by combining a liquid-permeable surface material and a leakproof backing material, and by making the leakproof backing material a nonwoven fabric, the diaper is waterproofed. It imparts breathability without deteriorating the properties, and further, in the dry method, spun bond method, thermal bond method, stitch bond method or needle punch method, from saturated saturated polyester treated with a coupling agent, and in the melt blown method. Is a non-woven fabric produced from an aliphatic saturated polyester resin that has been treated with a coupling agent or is untreated. Material, succeeded in developing a good extremely touch diaper by using the side portion or the like to achieve the above objects.

In the present invention, the liquid absorbing material may be biodegradable, and may be a high absorbent polymer used in conventional disposable diapers put in fluff pulp or the like.

In the polyester prepolymer for obtaining the aliphatic polyester resin used in the present invention, the terminal group obtained by reacting glycol with an aliphatic dibasic acid or an anhydride thereof is substantially a hydroxyl group, It is a saturated aliphatic polyester having a relatively high molecular weight of 5,000 or more, preferably 10,000 or more and a melting point of 60 ° C. or more.

When the number average molecular weight is less than 5,000,
Even if a small amount of coupling agent of 0.1 to 5 parts by weight is used, a polyester having good physical properties cannot be obtained. A polyester prepolymer having a number average molecular weight of 5,000 or more can be used to synthesize a high molecular weight polyester by using a small amount of a coupling agent without forming a gel during the reaction even under severe conditions such as a molten state.

Examples of glycols used include ethylene glycol, 1,4-butanediol, and 1,6.
-Hexanediol, decamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like can be mentioned. Ethylene oxide can also be utilized. You may use these glycols together.

Aliphatic dibasic acids or their acid derivatives which react with glycols to form aliphatic polyesters include succinic acid, adipic acid, suberic acid, sebacic acid,
There are dodecanoic acid, succinic anhydride, adipic anhydride, and lower alcohol esters such as dimethyl ester, which are commercially available and can be used in the present invention. You may use together these aliphatic dibasic acid or its acid derivative.

These glycols and dibasic acids are mainly aliphatic, but a small amount of other components such as trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids may be used in combination. preferable.

The trifunctional polyhydric alcohol component is typically trimethylolpropane, glycerin or its anhydride, and the tetrafunctional polyhydric alcohol component is typically pentaerythritol.

As the trifunctional oxycarboxylic acid, malic acid is practically advantageous, and as the tetrafunctional oxycarboxylic acid component, citric acid is practical because commercial products can be easily obtained at low cost.

As the trifunctional polyvalent carboxylic acid (or acid anhydride thereof) component, for example, trimesic acid, propanetricarboxylic acid, etc. can be used, but trimellitic anhydride is advantageous in practical use.

Examples of the tetrafunctional polyvalent carboxylic acid (or acid anhydride thereof) include pyromellitic dianhydride, benzophenonetetracarboxylic acid anhydride, cyclopentanetetracarboxylic acid anhydride and the like.

The polyfunctional component is used in such a proportion that the glycol component, the aliphatic component (including cycloaliphatic component), or the dicarboxylic acid (or its acid anhydride) component has a molar ratio of 10 or less.
In the case of a trifunctional component, 5 mol% or less with respect to 0 mol%,
It is preferably 0.5 mol% or more and 3 mol% or less, and in the case of a tetrafunctional component, 3 mol% or less, preferably 0.2 mol%
It is 2 mol% or less.

If the proportion of the trifunctional component used is more than 5 mol%, or if the proportion of the tetrafunctional component used is more than 3 mol%, the risk of gelation during the esterification reaction increases significantly.

The polyester prepolymer for an aliphatic polyester used in the present invention has a terminal group substantially a hydroxyl group. For that purpose, glycols and dibasic acid (or its acid anhydride) used in the synthesis reaction are used. The use ratio of is required to use some excess of glycols.

The synthesis of relatively high molecular weight polyester prepolymers requires the use of a deglycolization catalyst during the deglycolization reaction following esterification.

Examples of the deglycolization catalyst include acetoacetoyl type titanium chelate compounds and titanium compounds such as organic alkoxy titanium compounds.
These titanium compounds can be used in combination. Examples of these include diacetoacetoxyoxytitanium ("Narsem titanium" manufactured by Nippon Kagaku Sangyo Co., Ltd.), tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium and the like. The titanium compound is used in an amount of 0.001 to 100 parts by weight of the polyester prepolymer.
It is 1 part by weight, preferably 0.01 to 0.1 part by weight.
The titanium compound may be added from the beginning of esterification or immediately before the deglycolization reaction.

As a result, the polyester prepolymer usually has a number average molecular weight of 5,000 or more, preferably 10,000.
It is more preferable that those having a melting point of 0 or higher and a melting point of 60 ° C. or higher can be easily obtained and have crystallinity.

To obtain the aliphatic polyester resin of the present invention, a polyester prepolymer having a number average molecular weight of 5,000 or more, preferably 10,000 or more, whose terminal group is substantially a hydroxyl group, is further added. Coupling agents are used to increase the average molecular weight.

When the aliphatic polyester which is not subjected to the coupling treatment is used, it is not necessary that the terminal group is a hydroxyl group, but it is particularly necessary that the esterification is sufficiently carried out, and the MFR (190 ° C.) is at least 300. ~
A flow characteristic of about 1000 g / 10 minutes is required.

In the coupling treatment, the polyester prepolymer is reacted with a coupling agent to obtain an aliphatic saturated polyester resin having a higher molecular weight. As the coupling agent, diisocyanate, oxazoline, diepoxy compound, acid anhydride and the like can be used, but diisocyanate is particularly preferable in terms of reactivity and performance of the obtained polyester.

The type of diisocyanate is not particularly limited, but for example, 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate and 2,6-
Mixture with tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate,
Isophorone diisocyanate or the like can be used,
Particularly, hexamethylene diisocyanate is preferable from the viewpoint of the hue of the produced resin and the reactivity when adding polyester.

When an oxazoline or diepoxy compound is used as the coupling agent, the hydroxyl group of the prepolymer is reacted with an acid anhydride or the like to convert the hydroxyl group terminal into a carboxyl group before using the coupling agent. It is necessary.

The amount of the coupling agent added varies depending on whether it is a film or a non-woven fabric, and whether the non-woven fabric is formed by the spun bond method or the melt blown method. It is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight with respect to parts by weight.

If it is less than 0.1 part by weight, the coupling reaction is insufficient, and if it exceeds 5 parts by weight, gelation tends to occur.

The addition is preferably carried out under the condition that the polyester prepolymer is in a uniform molten state and can be easily stirred. It is not impossible to add it to a solid polyester prepolymer, melt it through an extruder, and mix it, but in an aliphatic polyester production equipment,
Alternatively, it is practical to add it to a polyester prepolymer in a molten state (for example, in a kneader), but the manufacturing method is not limited to this.

In particular, when the resin is used in the melt blown method, the resin which has been treated with the coupling agent and has a good flowability, or when the resin having a low melt viscosity is required, the resin which is not treated with the coupling agent may be used.

When the above polyester resin is used for molding the disposable diaper material according to the present invention, if necessary, an antioxidant, a heat stabilizer, an ultraviolet absorber, etc., as well as a lubricant, a wax agent, a coloring agent. Of course, a crystallization accelerator and the like can be used in combination.

That is, as the antioxidant, hindered phenolic antioxidants such as pt-butylhydroxytoluene and ptbutylhydroxyanisole, and sulfur such as distearylthiodipropionate and dilaurylthiodipropionate. Triphenyl phosphite, trilauryl phosphite, trisnonyl phenyl phosphite, etc. as the system antioxidant and heat stabilizer, and pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone as the ultraviolet absorber. 2-hydroxy-4-methoxy-2'-carboxybenzophenone,
2,4,5-trihydroxybutyrophenone and the like, lubricants such as calcium stearate, zinc stearate, barium stearate and sodium barmitate, and antistatic agents such as N, N-bis (hydroxyethyl) alkylamines and alkylamines. Alkyl allyl sulfonate, alkyl sulfonate, etc., flame retardant hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, etc., inorganic fillers calcium carbonate, silica, titanium oxide, As crystallization accelerators such as talc, mica, barium sulfate, and alumina, polyethylene terephthalate, poly-transcyclohexanedimethanol terephthalate and the like can be mentioned.

The liquid-permeable surface material of the present invention uses the biodegradable polyester resin thus obtained as a nonwoven fabric. The leak-proof backing material is either a film or a non-woven fabric.

When it is used as a film, it can be formed by a method such as an inflation method or a T-die method as in the case of a usual thermoplastic resin. In this case, however, as in other resins, calcium carbonate or the like is used. It is also possible to extrude a mixture of fillers, form a film, stretch it, and emboss it with a satin finish to obtain a leak-proof backing material having air permeability. The film thickness in this case is also 20
When the thickness is about 50 μm, a leak-proof backing material having substantially the same mechanical strength, flexibility, waterproofness, and breathability and having biodegradability is obtained.

However, the air permeability of the film in which the filler is blended and stretched to have fine pores is still insufficient, and considerable stuffiness cannot be avoided. The present invention also developed a leak-proof backing material that is breathable without impairing waterproofness as well as biodegradability.

Nonwoven fabric obtained by laminating webs produced from the above polyester resin by the spunbond method (generally 0.3 to 10d is obtained) and the melt blown method (generally 0.01 to 1d is obtained). It was found that when used as a leak-proof backing material, it becomes a biodegradable disposable diaper that is impermeable to water and breathable.

The polyester resin of the present invention can be easily changed in melting characteristics depending on the molecular weight of the polyester prepolymer and the compounding amount of the coupling agent, and the obtained fiber (nonwoven fabric) can be easily subjected to thermal bonding. Non-woven fabrics can be produced with extremely high productivity by the spunbond method, meltblown method, stitch bond method, needle punch method and the like.

At this time, the non-woven fabric of the leakproof backing is constituted by superposing 95 to 50% by weight of the spunbond method web and 5 to 50% by weight of the melt blown method, or by mixing the fibers on a line. It is preferable to use a nonwoven fabric. Non-woven fabrics made by the spunbond method alone have high air permeability and poor waterproofness, while non-woven fabrics made by the melt blown method alone have good waterproofness but low strength.Thus, increase the thickness of the non-woven fabric to have the same strength. I need it.

In the case of a non-woven fabric in which the spunbond method and the meltblown method are mixed or laminated, it is preferable that the meltblown method, which is a fine fiber, is placed inside (the side in contact with the skin).

The leakproof backing material has a waterproof pressure of 1000 m.
mH ₂ O or more, water vapor transmission rate 2500 to 6000 g / m ² · 2
4hrs, air permeability 200-1000sec / 100cc
A property of a certain degree is preferable, and this is easily obtained by a non-woven fabric obtained by mixing webs of the spunbond method and the meltblown method. Waterproof strength is 2000 by using non-woven fabric
If it is at least mmH ₂ O, it has a moisture permeability of 2,500 to 600, which is comparable to a film with almost no water permeability.
0g / m ² · 24hrs, air permeability 700~900sec
Since a high value of / 100 cc can be maintained, stuffiness caused by the diaper can be greatly reduced and diaper rash can be greatly reduced.

On the other hand, as a nonwoven fabric of liquid-permeable surface material,
When a nonwoven fabric produced from the above polyester resin is used, a thick fiber web or nonwoven fabric obtained by subjecting the polyester resin of the present invention to a thermal bond method (core-sheath method), a spun bond method, or the like is used.

Both the web and the non-woven fabric are breathable, and unlike cotton and pulp-based tissues, they have a low water absorption property, and therefore have a good texture.

Further, as the side portion of the liquid-permeable surface material, which is particularly required to have water repellency, a non-woven fabric made of the polyester resin by the melt blown method and the spun bond method is used. At this time, the strength of the melt-blown method alone is insufficient, and the strength of the spunbond method alone is not sufficient, but the water repellency tends to be insufficient due to the thick fibers. When the liquid-permeable surface material and the leak-proof backing material are made of the same polyester resin, thermal bonding becomes extremely simple, which provides an advantage that a disposable diaper can be manufactured with high productivity.

In the disposable diaper, needless to say, waist bands other than fluff pulp, elastic, etc. made of this polyester resin are also preferable for biodegradability.

[0049]

In the present invention, the liquid-permeable surface material of the disposable diaper is made of biodegradable polyester resin, combined with the biodegradable leakproof backing material, and the entire diaper is made biodegradable. Is a complete solution to the problem of environmental destruction.

In particular, by making the leak-proof backing material a non-woven fabric, it has been possible to give breathability without lowering the waterproof property and reduce the stuffiness of the diaper.

Further, by using the above-mentioned biodegradable polyester resin as the liquid-permeable surface material, a web or a nonwoven fabric produced by a thermal bond (core-sheath method) or a spunbond method can be used, and a diaper can be produced by thermal bonding. Made it possible to improve productivity.

[0052]

EXAMPLES The present invention will be described below with reference to examples and comparative examples.

[Synthesis Method of Resin] (Resin A) After replacing 700 L of the reactor with nitrogen,
183 kg of 4-butanediol and 224 kg of succinic acid were charged. The temperature is raised under a nitrogen stream and the temperature is 192-220 ° C.
For 3.5 hours, further stop nitrogen, 20 ~ 2mmHg
The esterification reaction by dehydration condensation was performed under reduced pressure for 3.5 hours. Acid value of the collected sample is 9.2 mg
/ G, the number average molecular weight (Mn) was 5,160, and the weight average molecular weight (Mw) was 10,670. Subsequently, 34 g of tetraisopropoxy titanium, which is a deglycolization reaction catalyst, was added under a nitrogen stream under normal pressure. Raise the temperature to 15 ~ 0.2mmHg at 215 ~ 220 ℃
The deglycolization reaction was performed under reduced pressure for 5.5 hours.
The sample collected has a number average molecular weight (Mn) of 16,80.
0, and the weight average molecular weight (Mw) was 43,600. The yield of this polyester prepolymer was 339 kg when condensed water was removed.

Hexamethylene diisocyanate 5.42 was added to a reactor containing 339 kg of the polyester prepolymer.
Kg was added, and the coupling reaction was performed at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelation occurred. Then Irganox 101 as an antioxidant
0 (manufactured by Ciba Geigy) and 1.70 Kg of calcium stearate as a lubricant were added, and stirring was continued for further 30 minutes.

The reaction product was extruded into water with an extruder and cut into pellets with a cutter. 90
The yield of the polyester resin after vacuum drying at 6 ° C. for 6 hours was 300 kg.

The aliphatic saturated polyester resin A thus obtained was a slightly ivory-like white waxy crystal having a melting point of 110 ° C., a number average molecular weight (Mn) of 35,500 and a weight average molecular weight (Mw) of 170,000. , MFR (190
℃) is 1.0 g / 10 minutes, temperature 190 ℃, shear rate 10
The melt viscosity at ⁰ sec ⁻¹ was 1.5 × 10 ⁴ poise.

The average molecular weight is measured by Shodex GP.
C System-11, the solvent was a solution of CF ₃ COONa in 2 mmol of hexafluoroisopropyl alcohol, the concentration was 0.1% by weight, and the calibration curve was from Showa Denko KK PMMA standard sample Shodex Standard M-75.
I went there.

(Resin B) A 700 L reactor was purged with nitrogen, and then 200 kg of 1,4-butanediol, 250 kg of succinic acid and 2.84 kg of trimethylolpropane were charged. The temperature is raised under a nitrogen stream and the temperature is 192-220 ° C.
For 3.5 hours, further stop nitrogen, 20 ~ 2mmHg
The esterification reaction by dehydration condensation was performed under reduced pressure for 3.5 hours. Acid value of the collected sample is 2.5 mg
/ G, the number average molecular weight (Mn) was 8,660, and the weight average molecular weight (Mw) was 9,520. Then,
37 g of tetraisopropoxy titanium as a catalyst was added under a nitrogen stream under normal pressure. Increase the temperature to a temperature of 215-22
The deglycol reaction was performed at 0 ° C. under a reduced pressure of 15 to 0.3 mmHg for 8.0 hours. The sample collected had a number average molecular weight (Mn) of 16,200 and a weight average molecular weight (M
w) was 67,900. The yield of this polyester prepolymer was 367 Kg when condensed water was removed.

330 g of hexamethylene diisocyanate was added to a reactor containing 367 kg of the polyester prepolymer.
Was added and a coupling reaction was carried out at 170 to 185 ° C. for 1 hour. The viscosity increased rapidly but no gelation occurred. Then Irganox 1010 as an antioxidant
(Manufactured by Ciba Geigy) and 370 g of calcium stearate as a lubricant were added, and stirring was continued for another 30 minutes.

The reaction product was extruded into water with an extruder and cut into pellets with a cutter. 90
The yield of the polyester resin after vacuum-drying at 6 ° C. for 6 hours was 360 Kg.

The obtained aliphatic saturated polyester resin B is a slightly ivory-like white waxy crystal having a melting point of 110 ° C., a number average molecular weight (Mn) of 25,600 and a weight average molecular weight (Mw) of 122,000. , MFR (190
18 ° C./10 minutes, temperature 190 ° C., shear rate 100
The melt viscosity at sec ⁻¹ was 4.0 × 10 ⁴ poise.

The average molecular weight is measured by Shodex GP.
C System-11, the solvent was a solution of CF ₃ COONa in 2 mmol of hexafluoroisopropyl alcohol, the concentration was 0.1% by weight, and the calibration curve was from Showa Denko KK PMMA standard sample Shodex Standard M-75.
I went there.

(Resin C) A 700 L reactor was purged with nitrogen, and then 196 kg of 1,4-butanediol and 204 kg of succinic acid were charged. The temperature is raised under a nitrogen stream,
5.0 hours at 0-220 ℃, stop nitrogen further 15
The esterification reaction by dehydration condensation was performed for 3.5 hours under a reduced pressure of ˜2 mmHg. The sample collected had an acid value of 8.5 mg / g and a number average molecular weight (Mn) of 5,20.
0, and the weight average molecular weight (Mw) was 10,100. Subsequently, 30 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream under normal pressure. Raise the temperature,
The deglycol reaction was carried out at a temperature of 215 to 220 ° C. under a reduced pressure of 5 to 0.2 mmHg for 15 hours. The sample collected had a number average molecular weight (Mn) of 23,300 and a weight average molecular weight (Mw) of 89,300. The theoretical yield of this polyester prepolymer is 327K, excluding condensed water.
It was g.

327 kg of polyester prepolymer 1
After cooling to 80 ° C., 41 g of phosphorous acid as an anti-coloring agent, 327 g of Irganox B225 (manufactured by Ciba Geigy) as an antioxidant and 327 g of calcium stearate as a lubricant were added to the reactor, and stirring was continued for another 30 minutes. It was This reaction product was extruded into water with an extruder and cut into pellets with a cutter. 90 ° C
The yield of the polyester resin C after vacuum drying for 6 hours was about 310 kg.

Obtained aliphatic saturated polyester resin C
Is a white solid crystal having a melting point of 120 ° C., a number average molecular weight (Mn) of 23,100 and a weight average molecular weight (Mw) of 9.
0,500, MFR (190 ℃) is about 500g / 10
The viscosity of a 10% solution of orthochlorophenol is 20.
The melt viscosity at a poise, a temperature of 190 ° C., and a shear rate of ^{1 to} 10 sec ⁻¹ was 100 poise (Tokimec, rotational viscometer). The average molecular weight is measured by Shodex G
PC System-11 (Showa Denko KK gel chromatography), solvent of CF ₃ COONa HFIPA
5 mmol solution, concentration 0.1% by weight, calibration curve shows Showma Denko KK PMMA standard sample ShodexStand
ard M-75.

(Resin D) A 700 L reactor was purged with nitrogen, and then 222.5 kg of 1,4-butanediol and 277.5 kg of succinic acid were charged. The temperature was raised under a nitrogen stream, and the esterification reaction by dehydration condensation was performed at 195 to 210 ° C. for 5.0 hours, and further, nitrogen was stopped and the pressure was reduced at 15 to 5 mmHg for 3.5 hours. The sample collected 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 11,20.
It was 0. Subsequently, 50 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream under normal pressure. Raise the temperature to 5 to 0.2 mmH at a temperature of 215 to 220 ° C.
The deglycol reaction was performed for 7.5 hours under a reduced pressure of g.
The sample collected has a number average molecular weight (Mn) of 17,20.
0, and the weight average molecular weight (Mw) was 58,700. The theoretical yield of this polyester prepolymer was 415.5 Kg when condensed water was removed.

The polyester prepolymer 415.5K
Irganox 101 as an antioxidant in a reactor containing g
0 (manufactured by Ciba Geigy), 416 g of calcium stearate as a lubricant, 52 g of phosphorous acid as an anti-coloring agent, and 3.74 kg of hexamethylene diisocyanate were added, and a coupling reaction was performed at 160 to 200 ° C. for 2 hours. It was The viscosity increased rapidly but no gelation occurred.

The reaction product was extruded into water by an extruder and cut into pellets by a cutter. 90
The yield of polyester resin D after vacuum drying at 6 ° C. for 6 hours was about 410 kg.

The obtained aliphatic saturated polyester resin D is a white solid crystal having a melting point of 120 ° C. and a number average molecular weight (M
n) is 26,700, the weight average molecular weight (Mw) is 98,
000, MFR (190 ° C.) was 120 g / 10 minutes, the temperature was 190 ° C., and the melt viscosity at a shear rate of ^{1 to} 10 sec ⁻¹ was 700 poise (Tokimec, rotational viscometer).

The pellets of these resins were dried using a dew-point controlled hot air circulation dryer at 100 to 120 ° C. for 2 to 4 hours and then subjected to molding.

[Inflation film] Calcium carbonate is blended with resin A, a 60 mmφ extruder is used with a circular die having a lip gap of 1.2 mm and 300 mmφ, a blow-up ratio of 3.0 times, and a take-up speed of 135 m.
After making an inflation film having a thickness of 30 μm / min, a satin-finished film was obtained. Strength is MD direction 65
The tensile strength was 0 kg / cm ² , the TD direction was 670 kg / cm ² , and the elongation was 660% in the MD direction and 790% in the TD direction.

[Spunbond-Meltblown Nonwoven Fabric] A nonwoven fabric molding apparatus capable of molding a spunbond nonwoven fabric and a meltblown nonwoven fabric in an in-line type manufacturing process was used. Spunbond method uses resin B with a die width of 100
65m with 0mmφ, 200 holes x 5 rows of dies
An mφ extruder is used. In the melt blown method, resin C is usually used as a high-speed injection gas flow by using a 40 mmφ extruder equipped with a die of 1000 holes × 1 row at a pitch of 1 mm.
Superheated steam of 5 kg / cm ² G was used. Filaments spun by the spunbond method were deposited on a collect conveyer and pressed with a pair of hot pressing devices consisting of a flat roll and an engraving roll to obtain a spunbond nonwoven fabric. The spunbond-meltblown method non-woven fabric is spun, mixed and deposited with a meltblown method filament that is jetted onto the web of spunbond filaments being conveyed by a collect conveyor, conveyed, and pressed by a heat-pressing device to form SB. -MB mixed fiber non-woven fabric.

[Thermal Bond Nonwoven Fabric]
Using a 40 mmφ extruder equipped with a 6 mmφ, 68-hole multifilament nozzle, continuous extrusion and stretching,
The drawn yarn was crimped and cut into a staple fiber having a length of 52 mm. 3. As a single fiber
The denier was 3 denier, the strength was 42 g / d, and the elongation was 43%. This cotton was deposited by a cutting machine, made into a web, and pressure-bonded with a calendar roll to obtain a thermal bond nonwoven fabric.

[Sewing of diaper] A super absorbent polymer was put into fluff pulp, and a walnut solution absorbing part was made with absorbent paper. A diaper was formed by bonding a film or a non-woven fabric on the front and back surfaces of the liquid absorbing material.

Example 1 A fluff pulp in which a resin B is used as a liquid-permeable surface material, a spunbonded nonwoven fabric having a basis weight of 20 g / m ² and a thickness of 0.19 mm is incorporated with a super absorbent polymer as a liquid absorbing material. And a resin A as a leak-proof backing material, and an inflation film having a thickness of 30 μm was combined to form a biodegradable disposable diaper. The performance of the materials used is shown in Table 1. 200 artificial urine in this diaper
When it was buried in soil after absorbing cc, the whole was almost completely corroded and decomposed after 3 months.

Example 2 Resin B was used as the liquid-permeable surface material, a thermal bond nonwoven fabric having a basis weight of 20 g / m ² and a thickness of 0.22 mm was used, and the liquid-absorbent material and the leakproof backing material were used in Example 1. Used the same. The performance of the materials used is shown in Table 1. When it was buried in the soil in the same manner as in Example 1, the whole was almost decomposed after 3 months.

(Example 3) A thermal bond web having a basis weight of 45 g / m ^{2 made} of resin B as a leakproof backing material,
A melt-blown web of resin C having a basis weight of 15 g / m ² is laminated and pressed with an embossing roll to produce a basis weight of 60 g /
A disposable diaper was produced in the same manner as in Example 2 except that a non-woven fabric of m ² and a thickness of 0.5 mm was used. The performance of the materials used is shown in Table 1. When this diaper was subjected to the same biodegradability test as in Example 1, it was found to be almost completely corroded and decomposed in 3 months.

Example 4 As a leak-proof backing material, a spun-bonded web made of resin B and having a basis weight of 45 g / m ² was mixed and deposited with a melt-blown web made of resin D and having a basis weight of 15 g / m ^2. A disposable diaper was produced in the same manner as in Example 1 except that the nonwoven fabric having a basis weight of 60 g / m ² was used by pressing. The performance of the materials used is shown in Table 1.
When this diaper was subjected to the same biodegradability test as in Example 1, it was found to be almost completely corroded and decomposed in 3 months.

Example 5 As a liquid-permeable surface material, a spunbond web made of resin B and having a basis weight of 18 g / m ² was mixed and deposited with a meltblown web made of resin C and having a basis weight of 2 g / m ^2. , This is pressed and the basis weight is 20g /
A disposable diaper was produced in the same manner as in Example 1 except that the nonwoven fabric of m ² was used. The performance of the materials used is shown in Table 1. When this diaper was subjected to the same biodegradability test as in Example 1, it was found to be almost completely corroded and decomposed in 3 months.

[0080]

[Table 1]

[0081]

According to the present invention, since a non-biodegradable thermoplastic film or the like has been used as the liquid-permeable surface material and the leakproof backing material of a disposable diaper, the liquid-absorbent material is biodegradable. Despite the use of certain materials
The biodegradability of the diaper as a whole was lost, making it impossible to adopt a disposal method such as burial in the soil. Therefore, the only way to complete the treatment is by incineration, which has been a burden on the incinerator where the capacity is insufficient.

The present invention can solve the above problems by reacting a saturated polyester prepolymer having a terminal hydroxyl group as a raw material for a liquid-permeable surface material and a leak-proof backing material with a coupling agent. Succeeded in making the entire diaper biodegradable by using a liquid-permeable surface material and a leak-proof backing material made of an aliphatic saturated polyester resin or an aliphatic saturated polyester resin which is not coupled with the resin. It is a thing.

These materials are made of a nonwoven fabric obtained by mixing or laminating a web produced by the spunbond method and the meltblown method with the polyester resin so that the air permeability of the entire diaper can be maintained without impairing biodegradability and waterproofness. It has been greatly improved and succeeded in reducing stuffiness caused by diapers.

The liquid-permeable surface material and the leak-proof backing material produced from the polyester resin are combined with a conventional liquid-absorbent material to obtain not only biodegradability, breathability and waterproofness but also mechanical strength. In addition, it is excellent in flexibility and texture, and also has good thermal bonding and heat setting properties, and can produce a biodegradable disposable diaper with high productivity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location // C08G 63/02 NLK 7107-4J (72) Inventor Takashi Fujimaki Noba-cho, Konan-ku, Yokohama-shi, Kanagawa 634-4-442 (72) Inventor Eiichiro Takiyama 4-12-4 Nishi-Kamakura, Kamakura City, Kanagawa Prefecture

Claims (4)

[Claims] 1. An aliphatic polyester resin obtained by reacting a liquid-absorbent material and an aliphatic saturated polyester prepolymer whose terminal group is substantially a hydroxyl group with a coupling agent, or the treatment with no coupling agent. A biodegradable disposable diaper characterized by combining a liquid-permeable surface material made of an aliphatic saturated polyester resin and a leak-proof backing material. 2. The biodegradable disposable diaper according to claim 1, wherein the leak-proof backing material made of an aliphatic polyester resin is a non-woven fabric. 3. The disposable diaper according to claim 1, wherein the leak-proof backing material made of an aliphatic polyester resin is a non-woven fabric in which webs produced by the spunbond method and the meltblown method are mixed or laminated. 4. A saturated aliphatic polyester treated with a coupling agent in a dry method, a spun bond method, a thermal bond method, a stitch bond method or a needle punch method, or a coupling agent in a melt blown method, or The biodegradable disposable diaper according to any one of claims 1 to 3, wherein a non-woven fabric produced from an untreated aliphatic saturated polyester resin is used as a liquid-permeable surface material, a side portion, or the like.