JPH0711515A - Polyester staple - Google Patents

Abstract

PURPOSE:To obtain a staple biodegradable in the case where it is buried in the soil, etc., and excellent in mechanical strength and hot melt adhesion. CONSTITUTION:This staple is made of an aliphatic polyester exhibiting 1.0X10<-2> to 1.0X10<4> poise melt viscosity at 190 deg.C and 1000sec<-1> shear rate and 70 to 190 deg.C melting point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a biodegradable, heat-stable, mechanical-strength, heat-meltable material molded from an aliphatic polyester having a practically sufficient high molecular weight and specific melting characteristics. The present invention relates to staples having excellent wearability.

[0002]

2. Description of the Related Art In recent years, synthetic resin (plastic) yarns, spun yarns, and woven fabrics having excellent productivity, strength, washability, etc. have been produced. There is a possibility of polluting rivers, oceans and soils, which has become a major social problem, and the emergence of biodegradable plastics has long been awaited to prevent this pollution. For example, poly (3-hydroxybutyrate) produced by a fermentation method using a microorganism, a blend of starch, which is a blend-type natural polymer, and a general-purpose plastic are known. However, the former has a drawback that the raw material unit is very bad because the thermal decomposition temperature of the polymer is close to the melting point, the moldability is poor, and microorganisms produce it. Further, in the latter, since the natural polymer itself is not thermoplastic, moldability is difficult and the range of use is greatly restricted. On the other hand, it has been known that aliphatic polyester has biodegradability, but it has hardly been used because a high-molecular-weight substance sufficient to obtain practical physical properties of molded articles cannot be obtained. Recently, ε-caprolactone was found to have a high molecular weight by ring-opening polymerization and has been proposed as a biodegradable resin, but its melting point is as low as 62 ° C. and the raw material is expensive, so it is limited to special applications. ing. Glycolic acid and lactic acid have high molecular weights obtained by ring-opening polymerization of glycolide and lactide, and are used in medical fibers and the like, but have melting points and decomposition temperatures close to each other, and have molding processability defects.
It has not been used in large quantities for threads and cloths.

This yarn, particularly spun yarn, non-woven fabric yarn, high molecular weight polyester usually used for forming staples as one of the materials for woven fabric (the high molecular weight polyester referred to herein has a number average molecular weight of 10). It is not an exaggeration to say that those having a molecular weight of 1,000 or more) are limited to polyethylene terephthalate, which is a condensate of terephthalic acid (including dimethyl terephthalate) and ethylene glycol. In some cases, 2,6-naphthalenedicarboxylic acid was used instead of terephthalic acid, but none of them has reported the attempt to impart biodegradability to the present situation. Therefore, conventionally, it can be said that there is no idea that a staple is formed using a biodegradable aliphatic polyester in which an aliphatic type is used as a dicarboxylic acid and the staple is put into practical use. One of the reasons why this idea of practical application has not been born is that even if the staple is crystalline even though a special molding material and molding property are required, the melting point of the aliphatic polyester is Is 10
Most of them are 0 ° C. or less, and the thermal stability when melted on the top is poor, and more importantly, the properties of this aliphatic polyester, particularly the mechanical properties represented by tensile strength, are Even if the number average molecular weight is the same as that of polyethylene terephthalate, the value is remarkably inferior, and it is considered that it was difficult to conceive the idea of obtaining a molded product requiring strength and the like. One of the reasons for this is that the research that expects to improve the physical properties by further increasing the number average molecular weight of the aliphatic polyester has not progressed sufficiently due to its poor thermal stability.

[0004]

DISCLOSURE OF THE INVENTION The present invention uses these aliphatic polyesters as its components, has a practically sufficient high molecular weight, and has mechanical properties represented by thermal stability and tensile strength, and thermal properties. It is an object of the present invention to provide a staple fiber which has excellent fusibility and is biodegradable as one of waste disposal means, that is, capable of being decomposed by microorganisms and the like, and which can be easily disposed of after use.

[0005]

Means for Solving the Problems As a result of various investigations on reaction conditions for obtaining a polyester having a high molecular weight and sufficient practicality and having staple formability, the present inventors have found that biodegradability is maintained. , A specific aliphatic polyester having a practically sufficient high molecular weight was obtained, and it was found that the multifilament molded from this has not only the above biodegradability, but also excellent thermal stability, tensile strength and flexibility. The present invention has been completed by cutting this multifilament into an appropriate length to obtain staples.

That is, the gist of the present invention is (A) a temperature of 190
Formed by extrusion molding using an aliphatic polyester having a melt viscosity of 1.0 × 10 ^{2 to} 1.0 × 10 ⁴ poise at a shear rate of 1,000 sec ⁻¹ and a melting point of 70 to 190 ° C. as a main component. The staple and (B) the aliphatic polyester have a number average molecular weight of 10,000 or more and 0.0
(A) staple containing 3 to 3.0% by weight of urethane bond, (C) number average molecular weight of 5,000 or more, melting point of 6
The staple of (A) or (B), which is obtained by reacting 100 parts by weight of an aliphatic polyester prepolymer at 0 ° C. or higher with 0.1 to 5 parts by weight of a diisocyanate. D) The staple of (A), (B) or (C) having a tensile strength of 2.0 to 10.0 g / d and a tensile elongation of 10 to 120%. Hereinafter, the content of the present invention will be described in detail.

The aliphatic polyester referred to in the present invention is mainly composed of polyester synthesized from glycols and polybasic acid (or its acid anhydride), and has hydroxyl groups at both ends in order to increase the molecular weight. A polyester prepolymer having a group and having a relatively high molecular weight is selected and further reacted with a coupling agent.

Conventionally, a low molecular weight polyester prepolymer having a hydroxyl group as a terminal group and a number average molecular weight of 2,000 to 2,500 is reacted with diisocyanate as a coupling agent to obtain a polyurethane, a rubber, It is widely used as foam, paint and adhesive. However, the polyester prepolymers used in these polyurethane foams, paints and adhesives are
The maximum number average molecular weight that can be synthesized without catalyst is 20,
It is a low molecular weight prepolymer having an amount of 0 to 2,500, and the amount of diisocyanate used is 10 to 20 parts by weight for 100 parts by weight of this low molecular weight prepolymer in order to obtain practical physical properties as a polyurethane. When such a large amount of diisocyanate is added to the melted low molecular weight polyester at 150 ° C. or higher, gelation occurs and a usual melt-moldable resin cannot be obtained.
Therefore, a polyester obtained by reacting such a low molecular weight polyester prepolymer as a raw material with a large amount of diisocyanate cannot be used as the raw material for the staple of the present invention.

As in the case of polyurethane rubber, a method of adding a diisocyanate to convert a hydroxyl group into an isocyanate group and further increasing the number average molecular weight with glycol can be considered. As described above, in order to obtain practical physical properties, the amount is 10 parts by weight or more based on 100 parts by weight of the prepolymer, and there is the same problem as above. If a relatively high molecular weight polyester prepolymer is used, the heavy metal-based catalyst necessary for the synthesis of the prepolymer remarkably promotes the reactivity of the above-mentioned amount of the isocyanate group, resulting in poor storage stability, crosslinking reaction, and branching. If the polyester prepolymer synthesized without a catalyst is used, the number average molecular weight is limited to 2,500, even if it is high.

The polyester prepolymer for obtaining the aliphatic polyester used in the present invention is of a relatively high molecular weight as described above containing the catalyst for its synthesis,
A saturated aliphatic polyester having a terminal group substantially a hydroxyl group, a number average molecular weight of 5,000 or more, preferably 10,000 or more and a relatively high molecular weight, and a melting point of 60 ° C. or more, and glycols. And a polybasic acid (or its anhydride) are subjected to a catalytic reaction. When the number average molecular weight is less than 5,000, for example, about 2,500, a polyester for staple having good physical properties cannot be obtained with a small amount of 0.1 to 5 parts by weight of the coupling agent used in the present invention. . A polyester prepolymer having a number average molecular weight of 5,000 or more has a hydroxyl value of 3
It is 0 or less, and by using a small amount of coupling agent, a high molecular weight polyester can be synthesized without producing a gel during the reaction because it is not affected by the remaining catalyst 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.

Polybasic acids (or their acid anhydrides) that react with glycols to form aliphatic polyesters include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid, succinic anhydride, and adipic anhydride. , Etc. are generally commercially available and can be used in the present invention. You may use together polybasic acid (or its acid anhydride).

These glycols and polybasic acids are mainly composed of aliphatic compounds, but small amounts of other components such as aromatic compounds may be used together. However, if other components are introduced, biodegradability deteriorates, so the content is 20% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less.

The polyester prepolymer for an aliphatic polyester used in the present invention has a terminal group which is substantially a hydroxyl group. For that purpose, glycols and polybasic acid (or its acid anhydride) used in the synthetic reaction are used. As for the use ratio of, it is necessary to use glycols in a slight excess.

The synthesis of relatively high molecular weight polyester prepolymers requires the use of a deglycolization reaction catalyst during the deglycolization reaction following esterification. Examples of the deglycolization reaction catalyst include titanium compounds such as acetoacetoyl type titanium chelate compounds and 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.

Further, the number average molecular weight is 5,000 or more,
Coupling agents are preferably used to increase the number average molecular weight of polyester prepolymers having 10,000 or more end-groups which are substantially hydroxyl groups. Examples of the coupling agent include diisocyanate, oxazoline, diepoxy compound, acid anhydride, and the like.
Diisocyanate is particularly preferable. In the case of an oxazoline or diepoxy compound, it is necessary to react the hydroxyl group with an acid anhydride or the like to convert the terminal into a carboxyl group before using the coupling agent. The type of diisocyanate is not particularly limited, but examples thereof include the following types. 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, Hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, particularly hexamethylene diisocyanate, are preferable from the viewpoint of the hue of the produced resin, the reactivity at the time of adding polyester, and the like.

The amount of these coupling agents added is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the polyester prepolymer. 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 and melt and mix it through an extruder, but add it to an aliphatic polyester production apparatus or to a molten polyester prepolymer (for example, in a kneader). It is practical to do so.

The aliphatic polyester used in the present invention is required to have specific melting characteristics in order to be extruded into staples. That is, the temperature is 190 ° C., the shear rate is 1,
The melt viscosity at 000 sec ⁻¹ is 1.0 × 10 ² ~
1.0 × 10 ⁴ poise, preferably 2.0 × 10
^{2 to} 6.0 × 10 ³ poise, 3.0 × 10 ^{2 to} 4.0 ×
10 ³ poise is particularly preferred. If it is less than 1.0 × 10 ² poise, the operability during spinning will be poor, and staples having sufficient strength cannot be obtained. If it exceeds 1.0 × 10 ⁴ poise, yarn breakage at the nozzle occurs, and spinning is difficult. The melt viscosity was measured with a nozzle diameter of 1.0 mm, a shear rate of 1,000 sec ⁻¹ was measured from a graph of the relationship between the shear rate and the apparent viscosity measured at a resin temperature of 190 ° C. using a nozzle of L / D = 10. The viscosity at time was determined.

Further, the melting point of the aliphatic polyester used in the present invention is required to be 70 to 190 ° C, more preferably 70 to 150 ° C, and particularly preferably 80 to 135 ° C. If it is less than 70 ° C, the heat resistance is insufficient, and if it exceeds 190 ° C, it is difficult to manufacture.
In order to obtain a melting point of 70 ° C or higher, the polyester prepolymer needs to have a melting point of 60 ° C or higher.

When the aliphatic polyester used in the present invention contains a urethane bond, the amount of the urethane bond is 0.03 to 3.0% by weight, preferably 0.05 to 2.0% by weight, 1 to 1.0% by weight is particularly preferred.
The amount of urethane bond is measured by C ₁₃ NMR and agrees well with the charged amount. If it is less than 0.03% by weight, the effect of increasing the molecular weight by the urethane bond is small and the moldability is poor,
If it exceeds 3.0% by weight, gel is generated.

When the above aliphatic polyester is used for forming the staple according to the present invention, if necessary, an antioxidant, a heat stabilizer, an ultraviolet absorber, etc., a lubricant,
Of course, waxes, colorants, crystallization accelerators and the like can be used in combination. That is, as the antioxidant, pt
Hindered phenolic antioxidants such as butylhydroxytoluene and pt-butylhydroxyanisole, sulfur antioxidants such as distearylthiodipropionate and dilaurylthiodipropionate, and triphenyl are used as heat stabilizers. Examples of ultraviolet absorbers such as phosphite, trilauryl phosphite, and trisnonylphenyl phosphite include p-t-butylphenyl salicylate and
2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone, etc.
As the lubricant, calcium stearate, zinc stearate, barium stearate, sodium palmitate, etc., and as the antistatic agent, N, N-bis (hydroxyethyl) alkylamine, alkylamine, alkylallyl sulfonate, alkyl sulfonate, etc. , As a flame retardant, hexabromocyclododecane, triso (2,3
-Dichloropropyl) phosphate, pentabromophenyl allyl ether and the like.

In the present invention, the raw material containing an aliphatic polyester as a main component is formed into fibers by melt spinning, air cooling, and hot drawing. The spinning temperature is 170 to 240 ° C, preferably 180 to 210 ° C. When the temperature is near the melting point, spinning breakage is likely to occur, and when the temperature exceeds 240 ° C., the sway of the yarn becomes large and the operability at the time of molding becomes extremely bad. Stretching is performed with a heating roll. The stretching temperature is 50 to 100 ° C,
It is preferably 70 to 90 ° C. If the temperature is lower than 50 ° C, the drawability is extremely reduced and a multifilament having sufficient physical properties cannot be obtained. If the temperature is 100 ° C. or higher, not only the drawability is extremely lowered, but also the breakage of the stretch is likely to occur, and the staple of stable quality cannot be obtained. This multifilament can be cut into an appropriate length to obtain staples. Further, the multifilament may be crimped so as to have texture and bulkiness, and then cut into an appropriate length to form a staple. This staple can be used as a raw material for spun yarn, a non-woven fabric, or a binder for a non-woven fabric. The multifilament using the aliphatic polyester according to the present invention has a tensile strength of 2.0 to 10 g.
/ D, the tensile elongation is 10 to 120%, which gives excellent staples.

[0024]

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

(Example 1) A 700-liter reactor was purged with nitrogen, and then 183 kg of 1,4-butanediol and 224 kg of succinic acid were charged. Raise the temperature under a nitrogen stream and
3.0 hours at 95-210 ℃, stop nitrogen further 1
The esterification reaction by dehydration condensation was performed for 3.5 hours under a reduced pressure of 5 to 5 mmHg. The sample collected is
Acid value 6.3 mg / g, number average molecular weight (Mn) 5,2
00, and the weight average molecular weight (Mw) was 10,100. Subsequently, 34 g of tetraisopropoxy titanium as a catalyst was added under a nitrogen stream under normal pressure. Raise the temperature,
The deglycolization reaction was carried out at a temperature of 215 to 220 ° C. under a reduced pressure of 5 to 0.2 mmHg for 7.5 hours. The sample collected had a number average molecular weight (Mn) of 18,600 and a weight average molecular weight (Mw) of 50,300. The yield of this polyester (A1) is 339 kg excluding condensed water.
Met.

4.07 kg of hexamethylene diisocyanate was added to a reactor containing 339 kg of polyester (A1), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelation occurred. Next, Irganox 1010 as an antioxidant
(Manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added, and stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into pellets with a cutter. The yield of polyester (B1) after vacuum drying at 90 ° C. for 6 hours was 270 kg.

The obtained polyester (B1) is a slightly ivory white waxy crystal and has a melting point of 110.
C., the number average molecular weight (Mn) is 29,500, the weight average molecular weight (Mw) is 127,000, the MFR (190 ° C.) is 9.2 g / 10 minutes, and the viscosity of a 10% solution of orthochlorophenol is 170 poises. Temperature 190 ℃, shear rate 10
The melt viscosity at 00 sec ⁻¹ was 3.0 × 10 ³ poise. The average molecular weight is measured by Shodex GPC.
System-11 (Showa Denko KK gel chromatography), solvent of CF ₃ COONa HFIPA5
mmol solution, concentration 0.1% by weight, calibration curve is Showma Denko KK PMMA standard sample ShodexStand
ard M-75.

0.6 mm using polyester (B1)
It was extruded at a discharge rate of 50 g / d using a 40 mmφ extruder with a multifilament spinning nozzle having φ and 68 holes. The extrusion temperature was 200 ° C. After the extruded unstretched multifilament was cooled in a cooling duct having a cooling temperature of 18 ° C., a cooling air velocity of 0.5 m / min and a length of 900 mm, the sizing agent was applied by a sizing agent application roller, and then 10
An unstretched multifilament having a total denier of about 4800 d was wound at a speed of 0 m / min. After that, using staple fiber-prototype tester, stretched up to 6 times, 51m
It was cut into a length of m to obtain staples. When the strength and elongation of the obtained staple were measured, it was 4.9 g / d and the elongation was 43%. When it was buried in the soil for 5 months in this stapled state, it was decomposed and changed to a state not having strength as a staple.

Example 2 Using polyester (B1), screw diameter 40 mmφ, nozzle diameter 0.6 mmφ,
Melt spinning was performed from a 68-hole extruder at a screw temperature of 190 ° C, a head temperature of 200 ° C, and a nozzle temperature of 205 ° C. The extruded unstretched multifilament was given a sizing agent with a roller, stretched 4 times at 70 ° C, and crimped with heated air at 80 ° C using a crimping nozzle to obtain a crimped yarn. . When the strength and elongation of the obtained crimped yarn were measured, the strength was 2.9 g / d and the elongation was 70%. In addition, JIS L
When the crimp rate and the crimp elastic modulus were measured according to 1036 and JIS L1074, the crimp rate was 10.7 and the crimp elastic modulus was 7.
It was 1.5. The crimp did not change even after heat treatment at 60 ° C. for 30 minutes. This crimped yarn is 5
It was cut to a length of 1 mm, deposited on a moving wire mesh material to give a web having a basis weight of 10 g / m ² , and then embossed into a nonwoven fabric. When this non-woven fabric was buried in the soil for 5 months, the strength of the fiber decreased and it was not in a practical state as a non-woven fabric.

(Comparative Example 1) Polyester (A1) was molded under the same conditions as in Example 1, but the stretch breakage was so great that the desired staple could not be obtained.

[0031]

According to the present invention, the temperature is 190 ° C. and the shear rate is 1.
Melt viscosity at 000 sec ⁻¹ is 1.0 × 10 ² ~
Staples having 1.0 × 10 ⁴ poise and a melting point of 70 to 190 ° C. as a main component, and particularly staples having a number average molecular weight of 5,000 or more and a melting point of 60 ° C. or more. To 100 parts by weight,
Staples made of aliphatic polyester obtained by reacting 0.1 to 5 parts by weight of diisocyanate have biodegradability when buried in soil or the like, and the calorific value of combustion even when incinerated. Is lower than polyethylene and polypropylene, has excellent mechanical strength and heat fusion properties, and can be used as a raw material for spun yarn, a nonwoven fabric, and a binder for a nonwoven fabric.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C08G 63/685 NNN 63/91 NLL D01F 6/84 306 B 7199-3B // B29K 67:00 ( 72) Inventor Eiichiro Takiyama 4-12-4 Nishi-Kamakura, Kamakura City, Kanagawa Prefecture

Claims (4)

[Claims] 1. A temperature of 190 ° C. and a shear rate of 1,000 se
Melt viscosity at c ⁻¹ is 1.0 × 10 ^{2 to} 1.0 × 10
^A staple formed by extrusion molding with an aliphatic polyester having a melting point of 70 to 190 ° C. having a poise of ⁴ as a main component. 2. The aliphatic polyester has a number average molecular weight of 1.
The staple according to claim 1, wherein the staple is at least 30,000 and contains 0.03 to 3.0% by weight of urethane bond. 3. A fat obtained by reacting 100 parts by weight of an aliphatic polyester prepolymer having a number average molecular weight of 5,000 or more and a melting point of 60 ° C. or more with 0.1 to 5 parts by weight of diisocyanate. The staple according to claim 1 or 2, wherein the staple is made of group polyester. 4. The staple according to claim 1, comprising a multifilament having a tensile strength of 2.0 to 10 g / d and a tensile elongation of 10 to 120%.