JPH04289222A - Divisible conjugate fiber and fiber aggregate thereof - Google Patents

Abstract

PURPOSE:To make it possible to readily divide a conjugate fiber by physical impact treatment of pressure water by using a heat-resistant compound capable of becoming a liquid phase at melt spinning temperature in at least part of interface between the first component and the second component of a conjugate fiber consisting of at least two or more components. CONSTITUTION:Silicone oil or modifier thereof is used as a heat resistant compound capable of becoming a liquid phase at melt spinning temperature and preferably finely dispersed in a polymer. Thereby a conjugate fiber can be readily divided with physical impact treatment of pressure water such as water jet, because silicon oil exists in the interface between the first component and second component by conjugate spinning even in combination of a polyester with the polyester or combination of a polyamide with the polyamide.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to composite fibers and aggregates thereof that can be easily split by physical impact treatment using a pressure fluid such as pressurized water.

0002

[Prior Art] Ultrafine fibers made of the same type of material, especially polyester or polyolefin, with irregularly shaped fiber cross sections have a high particle filtration effect, and are used in filter cloth, air filters, etc.
It is expected that this material will be used in industrial materials for filtration applications, such as canvas for paper making, which also require uniform chemical properties.

[0003] Conventionally, ultrafine fibers with uniform chemical properties, that is, made of the same material, are only ultrafine fibers made of island components by eluting the sea components of sea-island fibers. The process of elution and removal is uneconomical and wastes a large amount of resources.In order to solve these problems, we have developed ultrafine fibers with irregular cross sections that are made from splittable composite fibers using two different materials, although their chemical properties are non-uniform. was developed.

Conventionally, it has been known to utilize splittable conjugate fibers as a method for obtaining fine denier fibers. For example, Special Publication No. 53-47414, Special Publication No. 53-4741
No. 6, JP 63-14098 and JP 62-13
It has been proposed in various publications such as No. 3164.

[0005]

[Problems to be Solved by the Invention] However, the composite fibers disclosed in the above-mentioned publications are all combinations of different types of polymers as constituent units.

Examples include combinations of polyester and polyolefin, polyester and polyamide, and polyamide and polyolefin. These components are combined into a single fiber to make a composite fiber, so when this is divided to obtain fine denier fibers, it is natural that fibers made of different types of polymers are mixed together. Products made from this fiber have chemical resistance such as acid resistance, alkali resistance, solvent resistance, and moist heat resistance, thermal properties such as melting point, softening point, thermal decomposition temperature, maximum practical usable temperature, and types of compatible dyes. Each component has a mixture of chemical properties unique to it, such as dyeing properties such as the degree of dyeing. Regarding the filtration properties of simple particles, no matter which combination of splittable conjugate fibers is used, they all show better results than conventional filter cloths made of fibers with a circular cross section, but the constituent materials must have uniform chemical resistance. For industrial materials for filtration such as filter cloth and canvas for papermaking, conventional splittable conjugate fibers, such as polyester/polyamide combination fibers, are often not practical. In particular, it was desired to realize a splittable conjugate fiber made from a polyester/polyester combination, but the polyesters were highly compatible with each other (in some cases, a copolymerization reaction occurred at the interface), making it impractical to manufacture. There is a problem.

In addition, combinations of polyolefins/polyolefins such as polypropylene (PP)/high-density polyethylene (HDPE), or nylon-6 (NY6)/nylon-12 (NY1), which the present inventor has already proposed, may also be used.
2) Alternatively, splittable conjugate fibers made of a polyamide/polyamide combination such as MXD6 nylon (MXD6)/nylon-6 (NY6) are more splittable than conventional splittable conjugate fibers made of polyester/polyamide or polyester/polyolefin combinations. Therefore, improvements in divisibility are required for production purposes.

[0008] Conventional commercially available splittable composite fibers are fibers made of a combination of different thermoplastic resin components, so it is impossible to dye each component simultaneously with the same type of dye. There were also production and economic problems.

[0009] In order to solve the problems of the prior art, the present invention provides composite fibers and aggregates thereof that can be easily split by physical impact treatment with a pressure fluid such as pressure water.

0010

[Means for Solving the Problems] In order to achieve the above object, the splittable conjugate fiber of the present invention has a melting point (Tm°C) of 100
A composite fiber comprising at least a first component and a second component made of a thermoplastic resin in the range of <Tm<350,
A heat-resistant compound that becomes a liquid phase at the melt spinning temperature is present at least in a part of the interface between the first component and the second component, and at least one of the plurality of components is
Each component is a constituent unit of the fiber cross section, each constituent unit is adjacent to a constituent unit of a different component, and substantially most of each constituent unit is a constituent unit of the fiber cross section. It is characterized by a portion being exposed on the fiber surface.

[0011] In the above structure, it is preferable that the heat-resistant compound that becomes a liquid phase at the melt spinning temperature is an organopolysiloxane or a modified product thereof.

Furthermore, the fiber aggregate of the present invention contains at least 30% by weight of the splittable conjugate fibers, and has a structure in which the conjugate fibers are split.

[0013]

[Function] According to the configuration of the present invention, the heat-resistant compound that becomes a liquid phase at the melt spinning temperature exists at least in a part of the interface between the first component and the second component, and At least one component among the plurality of components is divided into two or more, each component is a constituent unit of the fiber cross section, and each constituent unit is adjacent to a constituent unit of a different component,
In addition, since most of the constituent units are partially exposed on the fiber surface, it is possible to form composite fibers and aggregates thereof that can be easily divided by physical impact treatment with pressure fluid such as pressurized water. can. Furthermore, it can be divided regardless of the type of polymer that is a component of the composite fiber.

Further, according to a preferred configuration of the present invention in which the heat-resistant compound that becomes a liquid phase at the melt spinning temperature is an organopolysiloxane or a modified product thereof, division becomes even easier.

Furthermore, according to the structure of the fiber aggregate of the present invention, it contains ultra-fine split fibers and has excellent entangled integrity, so it is useful for industrial materials for filtration such as filter cloth and papermaking canvas. It can be made into something.

[0016]

EXAMPLES The present invention will be explained in more detail below using examples. In addition, in the following examples, simply expressed as % means weight %. Considering the use of the thermoplastic resin used in the present invention, both the first component and the second component are preferably the same type of polymer such as polyesters, polyamides, polyolefins, etc., and may be completely the same polymer, but in practical use Considering production, even if the type is the same, the melting surface tension (γ; dyne/cm at 265°C) or the solubility parameter value (SP value δ: Cal1/2 cm
A combination of polymers with a large difference in the ratio of 3/2) is more preferable. For example, polyethylene terephthalate (PET), which is a combination of polyester/polyester
/Polybutylene terephthalate (PBT), polyolefin/PP/HDP which is a combination of polyolefin
NY6/NY which is a combination of E or polyamide
12. It is a combination of MXD6/NY6, but is not particularly limited to this.

Furthermore, even combinations such as PET/PET, which have never been considered as split fibers, can be split. As the thermoplastic resin that can be used, it is possible to use a resin with a melting point of 100 to 350°C, but for convenience of combination, a resin with a melting point of 100 to 300°C is preferable. Taking this into consideration, it is preferable to keep the spinning temperature (T°C) below 300°C, so a resin with a melting point of 100 to 270°C is most preferable, and resins with a melting point of less than 100°C are subject to restrictions such as stretching conditions during fiber production. It is easy to occur and is not desirable. Thermoplastic resins that can be used include polyesters (T) such as PET and PBT, nylon-6 (NY6), nylon-66 (NY66), and nylon-6,10 (NY
610), nylon-11 (NY11), nylon-1
Homopolymers and copolymers of polyamides (NY) such as 2 (NY12) and MXD6 nylon (MXD6), and polyolefins (O) such as PP, PE, polymethylpentene (PMP), ethylene copolymers, and propylene copolymers. and modified products are preferred, polycarbonate,
A thermoplastic resin having a melting point of 100 to 350°C, such as polystyrene, can be used.

[0018] The compound used in the present invention is kneaded into one of the thermoplastic resins and introduced into the fiber, and the first component and the second component are introduced through the compound using a method for three-component composite fibers. It can be introduced into the splittable conjugate fiber of the present invention by two methods: arranging it in the fiber cross-sectional structure in contact with each other. The compound used for the former is incompatible with both components, is liquid during melt spinning, and has a boiling point or thermal decomposition to gas so as not to gasify or produce a gaseous substance during melt spinning and cause the molten fiber to become foamed. Temperature at which temperature starts to occur (TB ℃
) is preferably 20°C or more higher than the melt spinning temperature (T°C), and the wettability (
Compounds with good affinity) are preferred, and compounds that are liquid at room temperature and easily removable after splitting are more preferred. Specific examples for which the effects of the present invention have been confirmed at present include silicone oils (hereinafter referred to as SiO) such as dimethylpolysiloxane and diphenylpolysiloxane, and alkene (C10 to C50) and propylene adducts of polymethylhydrogensiloxane (hereinafter referred to as NR- These include, but are not limited to, organopolysiloxanes (OS) such as B) and modified products and adducts thereof.

When using silicone oil to obtain splittable conjugate fibers of PET/PBT, for example, pellets with a particle size of 1 μm or less and 5% by weight or more of silicone oil kneaded are melted and prepared using a spinneret as shown in FIG. At the section, the molten resin flows from a direction perpendicular to the flow of molten resin 11, and is merged with other components flowing from a direction parallel to the flow of 12, so that the cross section becomes as shown in Fig. 1(c).
) in the form of fibers.

The vertical molten resin flow path 11 has a large contact area with the metal, and droplets of silicone oil condense and wet the metal surface, causing the resin to exit from the outlet of the flow path. Since each component joins with another component while being at least partially covered with silicone oil, both components form a fiber cross section in which they are in contact with each other via the silicone oil. In addition,
If both components are completely separated by silicone oil, they will fall apart during stretching, so when used as a staple, incomplete separation is preferred.

The latter method used in the present invention is illustrated in FIG.
When using the spinneret shown in FIG. 3, other compounds are added to the sea 13 of the compound (which may be a polymer in which silicone oil is finely dispersed, silicone oil, or a modified silicone) that becomes a liquid phase at the spinning temperature used in the present invention, as shown in FIG. The polymer component 12 is allowed to flow down to form a component covered with the compound 13 used in the present invention as shown in FIG. 4, and is merged with other components to form a fiber cross section where both components are in contact via the compound used in the present invention. It is. In addition to the compounds used in the former method example above, thermoplastic resins that are incompatible with both components can also be used as the compound used in the present invention, but after the splittable composite fiber of the present invention is split, Unless the compound is easy to remove or for applications where removal is unnecessary, it is not preferred because it causes the same drawbacks as conventional splittable fibers.

The fiber cross section of the splittable conjugate fiber of the present invention is shown in FIG.
At least one of the two components shown in (a) to (e) is divided into two or more parts, each component is a constituent unit of the fiber cross section, and each constituent unit is composed of different components. It has a structure that is adjacent to the structural unit and a part of it is exposed on the fiber surface, and the volume ratio of both components is 30/70 to 70/30.
It is preferable that it is in the range of . In addition, in the present invention, "substantially most of each structural unit has a part exposed on the fiber surface" means that each structural unit is separated to the extent that it can be divided by physical impact treatment with a fluid such as a water jet. This means that it is sufficient if it is exposed on the fiber surface. Therefore, for example, some constituent components may be present inside the fiber, or the entire fiber may be thinly coated with one constituent component for manufacturing reasons.

[0023] The splittable conjugate fiber of the present invention has a molecular weight of 0.5 to 100
denier fineness, preferably in fiber forms that are at least twice as drawn, such as multifilament, staple, and paper cut, and are crimped by physical folding methods such as stuffing boxes, or by carding machines. After performing a physical fiber splitting promotion treatment such as using a water jet device, the fiber can be further divided into fine fibers by a dividing treatment using a physical impact generating device such as a water jet device.

The splittable conjugate fiber of the present invention is polyester,
It can be used as a fiber aggregate mixed and/or layered with other fibers such as acrylic, nylon, and rayon or fibrous materials such as polp synthetic pulp.
The splitting treatment of the composite fibers may be performed either before or after mixing. The fiber aggregate refers to fiber processed products such as felt, nonwoven fabric, paper, spun yarn and its woven or knitted fabric, flocked products, multifilament and its woven or knitted fabric, and the composite fiber is at least partially contained in the fiber aggregate. It is contained in a divided state and exists as fine fibers that are effective for water retention and moisture retention, or as fibers with sharp corners in the fiber cross section that are easy to wipe off. In order to effectively exhibit these effects, it is preferable to contain at least 30% by weight of the composite fiber of the present invention.

The composite fibers of the present invention include splittable composite fibers of combinations of thermoplastic resins of the same type, such as polyester/polyester, polyolefin/polyolefin, and polyamide/polyamide, which are not considered conventional splittable fibers. It is now possible to divide combinations of ingredients that were not previously available. Furthermore, it is possible to separate a combination of identical thermoplastic resins, such as PET/PET, and this method is limited only by the heat resistance of the compound used to separate the two components and the heat resistance of both components. It is presumed that a combination of thermoplastic resins can also be used to create a splittable conjugate fiber.

In place of polyester fibers, which are extremely widely used in the field of general filtration media in particular, if splittable composite fibers of a combination of polyester/polyester are split and used as fine fibers, under the same usage conditions as before, This makes it possible to collect even finer particles than the conventional method, making it extremely useful. In addition, for filter media that requires both acid resistance and alkali resistance in fields where heat resistance is not so required, splittable composite fibers of a combination of PP/HDPE can be made much easier to split than when the present invention is not applied. Useful.

Furthermore, when the compound used in the present invention used as the third component is organopolysiloxane, even if it remains in the fiber, it has excellent heat resistance, acid resistance, alkalinity, and non-toxicity, so there are few restrictions on the use and it is convenient. is good. A specific experimental example will be explained below.

Examples 1 to 7, Comparative Examples 1 to 5 As shown in Tables 1 to 2, various combinations of thermoplastic resins were used in Figure 1(c).
) A composite fiber with a pinwheel-shaped cross section was melt-spun into an undrawn yarn. The volume ratio of both components is 50:50, and both components are divided into eight parts by the other component. The presence or absence of an interface between each component was determined by magnifying the fiber cross section of the undrawn yarn using a transmission optical microscope. The organopolysiloxane was added to the first component, and in the case of a combination of components with similar hues, a raw material coloring masterbatch was added lightly to the second component. The spun undrawn yarn was drawn in hot water at 95°C, mechanically crimped through a stuffer box while impregnated with a fiber treatment agent, and dried for 15 minutes in a net conveyor type hot air dryer at 110°C to a length of 45 mm. It was cut into staple fibers.

After forming this staple fiber into a web with a fabric weight of 90 g/m2 using a roller card,
The composite fibers were treated with water under a pressure of 0 kg/cm2 for 5 seconds to evaluate whether or not they would split.Furthermore, dyeing was carried out under the following conditions.

A. Split ratio refers to the number of split fibers out of 100 split conjugate fibers and is expressed in %.

B. Staining conditions and evaluation evaluation ◎: Dyeing was possible in a deep color. ○: Slightly light dyeing was possible. △: Only one component could be dyed. ×: Unable to dye.

a) In the case of disperse dye Kayalon Polyester Red BR-S; 1 g/l,
Texaton THS-100; pH of 0.3 g/l and ammonium sulfate 200 g/l and acetic acid 3.3 ml/l
It was immersed in a dye solution consisting of a conditioning solution of 10 ml/l at a bath ratio of 1:30 and subjected to high-pressure dyeing at 130°C for 30 minutes, followed by 2 g of soda ash.
/l and hydrosulfite; 80 containing 2g/l
It was treated in a bath at 0.degree. C. for 5 minutes and then dried to give a dyed product.

b) In the case of acid dyes Sumitomo Chemical Solar Pure Blue AFX 1 g/l, anhydrous sodium sulfate; 3.3 g/l and acetic acid 0.7 g/l as dyeing aids were used and boiled for 1 hour at a bath ratio of 1:30. It was dyed and dried to make a dyed product.

Example 8 After filling the molten resin channel on the PBT side of the spinneret with silicone oil having a higher viscosity than in Example 1 using the combination of Comparative Example 2, composite fibers were melt-spun in the same manner as in Comparative Example 2. death,
An undrawn yarn in which the amount of silicone oil was about 5% based on the weight of PBT was collected and treated in the same manner as in Example 2. The fiber cross section was clearer than in Example 2, and the split ratio of the fiber treated with 170 kg/cm2 pressure water for 5 seconds was 20%.

The above conditions and results are shown in Tables 1 and 2.

[0036]

[Table 1]

[0037]

[Table 2]

As explained above, the splittable conjugate fiber of this example is a combination of thermoplastic resins of the same type, which were conventionally thought to be difficult to decompose or cannot be split, and can be split. In particular, polyester/polyester combination fibers are advantageous in the field of industrial filters because they can collect even finer particles than conventional products, and because they are chemically inert, they are required to be used as medical nonwoven fabrics or to have both acid and alkali resistance. It was possible to easily split the polyolefin/polyolefin combination fiber. In addition, the nonwoven fabric obtained as described above had good intertwining of the split fibers and was integrated into a felt-like structure. Furthermore, due to the presence of silicone oil finely dispersed in the polymer, the nonwoven fabric had excellent water repellency.

[0039]

Effects of the Invention As explained above, according to the composite fiber of the present invention, the heat-resistant compound that becomes a liquid phase at the melt spinning temperature is the first
present at least in part at the interface between the component and the second component;
At least one of the plurality of components as viewed from the fiber cross-sectional direction
The component is divided into two or more parts, each component is a constituent unit of the fiber cross section, each constituent unit is adjacent to a constituent unit of a different component, and substantially the majority of each constituent Since a portion of the unit is exposed on the fiber surface, the composite fiber and its aggregate can be easily split by physical impact treatment with a pressure fluid such as pressurized water. Furthermore, it can be divided regardless of the type of polymer that is a component of the composite fiber.

Further, according to a preferred configuration of the present invention in which the heat-resistant compound that becomes a liquid phase at the melt spinning temperature is an organopolysiloxane or a modified product thereof, division becomes even easier.

Furthermore, the fiber aggregate of the present invention contains ultra-fine split fibers and has excellent entanglement integrity, so it is useful for industrial materials for filtration such as filter cloth and papermaking canvas. It can be done.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a composite fiber according to an embodiment of the present invention.

FIG. 2 is a conceptual model diagram of composite spinning according to an embodiment of the present invention.

FIG. 3 is a conceptual model diagram of composite spinning according to an embodiment of the present invention.

FIG. 4 is a conceptual model diagram of composite spinning according to an embodiment of the present invention.

[Explanation of symbols]

1 Component A 2 Component B 11 Flow path of silicone oil-dispersed polymer 12 Flow path of ordinary polymer 13 Flow path of silicone oil-dispersed polymer, silicone oil, or modified product thereof

Claims (3)

[Claims] Claim 1: Melting point (Tm°C) is 100<Tm<35
In a composite fiber composed of at least a first component and a second component made of a thermoplastic resin in the range of At least one of the plurality of components is divided into two or more components when viewed from the cross-sectional direction of the fiber, and each component is a constituent unit of the fiber cross-section, and each constituent unit is mutually divided. 1. A splittable conjugate fiber characterized in that it is adjacent to constitutional units of different components, and that substantially most of each constitutional unit has a part exposed on the fiber surface. 2. The splittable conjugate fiber according to claim 1, wherein the heat-resistant compound that becomes a liquid phase at the melt spinning temperature is an organopolysiloxane or a modified product thereof. 3. A fiber aggregate containing at least 30% by weight of the splittable conjugate fiber according to claim 1, wherein the conjugate fiber is split.