DK155803B - FLAMMABLE COMPOSITIVE POLYOLEFIN FIBERS AND PROCEDURES FOR PRODUCING THEREOF - Google Patents

Description

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DK 155803 B

The invention relates to composite fire retardant fibers and to a method of making them. More particularly, the fire retardant composite polyolefin fibers comprise two kinds of polyolefin polymers having different melting points and having the same or different fire retardants in the two different components.

Composite polyolefin fibers have very good adhesive properties in the heat and also other good physical and chemical properties, and they are also lightweight and inexpensive. They have therefore been used as fiber material for non-woven fabrics in various applications. Eg. they are suitable as materials for thin products such as textile fabric base, hygienic materials, napkins and diapers, and for thick products such as quilted goods, different types of felt, filters and 15 fibrous products and various materials for public works. However, fire retardant properties are usually required if the fiber materials are to be used indoors.

As far as methods for making polyolefin fibers are flame retardant, there is first and foremost a method of applying flame retardants to the polymeric raw material upon which the spinning is performed. However, the addition of flame retardants causes a great deal of various difficulties in terms of reduced productivity and quality, and difficulties also arise at the spinning stage, e.g. fiber breakage, reduced strength, rough surface and degraded adhesive in hot state. These difficulties are strongly noted in the case of thin fibers of 6 d / F or less, and especially in the case of composite fibers, in particular in the case of a low melting component of low viscosity.

In addition to the aforementioned process, there are also methods for coating fibers with a fire retardant or for blending fire retardant fibers, but in the case of these methods it is the case that then already formed fibers are first treated at a later stage, then the steps are complicated, the variations in the quality are large and the costs high, and therefore such processes are not usually performed.

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DK 155803 B

In connection with the present invention, it has been found that when the highest melting and the lowest melting component of the composite fibers each contains a fire retardant having a decomposition temperature which is 100 ° C higher than the melting points of the respective components and when this fire retardant has a particle size of 62 microns or less, it is possible to produce good quality fire retardant and adhesive composite fibers with small denier and 10 containing a relatively large amount of the fire retardant even in the lowest melting component, all in connection with good spinnability.

The invention also includes the production of fibers of this kind.

The invention relates to, therefore, fire retardant composite fibers comprising a high melting component fiber forming olefin polymer and an olefin polymer having a melting point of 10 ° C or lower than the high melting component melting low component and 20 having a fire retardant in the respective components, and these composite fibers are characterized in that in each component there is 3-15% by weight of a fire retardant having a decomposition temperature of 100 ° C or more than the melting point of the respective components, and 25 with a particle size of 62 microns or less, the total amount of flame retardant in the composite fibers as a whole being 5-10% by weight.

Further, there is disclosed a process for producing fire retardant composite fibers using a fiber-forming olefin polymer as a high melting component and an olefin polymer having a minimum melting point of at least 10 ° C as a low melting component, mixing a fire retardant with the respective components and the resulting 35 components undergo splicing of the two components followed by stretching and this method is property-

DK 155803 B

for example, mixing the respective components with a fire retardant having a decomposition temperature of 100 ° C or more than the melting point of the respective components and having a particle size of 62 microns, 5 to obtain an amount of fire retardant of 3-15% by weight, the total amount of fire retardant in the composite fibers being 5-10% by weight, and melting the resulting components at a temperature below the respective decomposition temperatures of the fire retardant into the respective components for their coalescence. ding.

In the case of composite fibers, it is usually possible to equip their ripple and adhesive properties with various special features depending on the combination of the components and it is also possible to use the fibers in similar applications. Composite fibers of the present invention also have different fields of application, and it is particularly advantageous for the fibers to lie side by side or as envelope and core so that the low melting component 20 may have a fiber cross-sectional ratio of 50% or more. so that the composite fibers have heat adhesive properties in accordance with the low melting component.

In this case, the component ratio (i.e., the ratio of the high melting component to the low melting component) is preferably in the range of 5: 5 to 3: 7 for the thickness of the low melting component of the fiber cross section.

The high melting component is preferably polypropylene or copolymers, which are generally composed of polypropylene having fiber formability. The low melting component is preferably polyethylene, ethylene-vinyl acetate copolymers having a vinyl acetate content of e.g. 1-10% by weight, which in the following is often shortened to E-VA as well as hydrolyzed products and mixtures of polyethylene with E-VA or hydrolyzed E-VA.

The respective content of fire retardant in the high melting and low melting component of the composite fibers is as mentioned in the range of 3-15% by weight, - 4 -

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and the total fire retardant content of the composite fibers as a whole is in the range of 5-10% by weight. If the content of fire retardant is lower than stated above, the fire retardant effect is low and if the content exceeds the specified ranges, the tensile strength of the fibers becomes poor so that the product becomes difficult to manufacture and of poor quality.

The fire retardants used in the present invention are those used in the prior art. Among these, organic halogen compounds are preferred, and examples include decabromodiphenyl oxide (decomposition temperature 350 ° C ), 2,2-bis (4- (2,3-dibromo-propoxy) -3,5-dibromo-phenyl) -propane (270 ° C), tris- (2,3-dibromo-propyl) -phosphate (260 ° C), bis- (3,5-dibromo-4-dibromopropyloxy-phenyl) -sulfone (280 ° C).

These flame retardants are also preferably used in admixture with the Sb £ 0 ratio of the flame retardant to from 1.5: 1 to 3: 1.

The fire retardants used in the present invention have a particle size of 62 microns or less, preferably 53 microns or less.

25 If the fire retardants contain particles over 62 microns, this results in a reduction in their productivity or quality due to clogging of the spinning nozzle, fiber breakage at the time of stretching and the formation of a surface of the fibers which reduces their heat adhesive properties.

The fire retardants having a particle size of 62 microns or less can be obtained by sieving commercially available fire retardants by known methods such as precipitation and cyclone treatment, and a simple method consists of sorting them through sieves of nominal diameter 62 or 53 microns.

The fire retardant composite fibers of the invention can be made with known melt spinning, and the apparatus used may also be known. Eg. a powdered polymer raw material with admixture of fire retardant is melted and extruded by means of a melt extrusion.

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apparatus, and the resulting melting mass is passed through a temperature controlled heating zone for heating to a certain temperature (hereinafter often referred to as the spin temperature). The melting and temperature control of the polymer is carried out in 5 separate passages for each component, and the respective components are individually guided in the appropriate ratio into the spinning nozzles, through whose holes they are spun together. In connection with the present invention, a fire retardant having a decomposition temperature of 100 ° C or more than the melting point of the components, preferably 40 ° C or more above the spinning temperature, is used for the respective components to avoid decomposition and consumption of the fire retardant at the time of the spinning. Stretchable filaments, which are obtained for the spinning, are stretched in optional conditions depending on the field of application. Usually the stretching is performed in a stretching ratio of 4 or more. As for the stretch temperature, temperatures in the range from the softening point of the low melting component up to a temperature which is 10 ° C below the melting point can be used, but the effect of the stretch temperature on the flame retardant properties is small.

According to the method of the present invention, it is possible to prepare composite fibers containing a large amount of fire retardant and with little fineness in connection with only rare fiber breakage due to clogging of the spinning nozzles or replacement of the spinning matrix, and in a very stable manner and in very long periods of time. Furthermore, according to the invention, the fire retardant composite fibers not only have good fire retardant properties, but despite the high content of fire retardant they have a smooth surface and good heat adhesive properties.

The invention will be explained in more detail in connection with the following examples. The terms and methods of inquiry used in these examples are as follows: - 6 -

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Particle size of flame retardant: this refers to the nominal dimensions of the masks in standard screens used for sorting, and denotes the largest particle size of the flame retardant.

5 Spinability: this is classified according to the number of fiber breaks per hour: o: one break or less, Δ: two breaks, x: three breaks or more.

10 Spinning nozzle life: this is classified according to the frequency of spinning nozzle replacements: o: 40 hours or more, Δ: 20-39 hours, x: less than 20 hours.

15 Adhesive strength: the relative value of the adhesive strength of a sample of non-woven fabric to a corresponding blank (ie, a non-woven fabric made in the same way as the sample, but without any fire retardant): ^ o: more than 90 %, 20 Δ: 70-90%, x: less than 70%.

Rough surface: the number of rough surface filaments among 100 filaments observed in microscope: o: 2 filaments or fewer, 25 Δ: 3-9 filaments, x: 10 filaments or more.

Container of fire retardant: Sb20 ^ is considered an additive different from the fire retardant.

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Flame retardant:

Number Name temperature 1 2,2-bis- (4- (2,3-dibromopropoxy) -

3,5-dibromophenyl) propane 270 ° C

2 bis- (3,5-dibromo-4-dibromopropyl)

oxyphenyl) sulfone 280 ° C

3 tris- (2,3-dibromopropyl) phosphate 260 ° C

4 decabromodiphenyloxide 350 ° C

Perchloropentacyclododecane 650 ° C

6 ethylenediamine dihydrobromide 355 ° C

7 1,2-dibromo-3-chloropropane 210 ° C

8 pentadibromo monochlorocyclohexane 230 ° C

Combustion test (JIS method): method according to JIS L1091 »15 Al (45 ° micro burner).

Combustion test (match method):

A sheet of nonwoven fabric is cut into a sample piece 3 cm long and 20 cm wide in the fiber direction. The resulting specimen is then secured to form an angle of 30 ° to the vertical surface and brought into contact with the flame of a match specimen at the lower end of the specimen from below. As the specimen ignites and the match specimen burns, the lower end of the specimen will burn and the flame will rise upward from the bottom 25. Precisely when the specimen has been ignited, the match specimen is removed and the time at which the ends of the specimen has a flame is measured. A sheet with a time of 5 seconds or less has passed the test, while a sheet with longer time is discarded.

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Examples 1-3 and Comparative Examples 1-4

A polyethylene (PE) having a melt flow rate MFR of 20 according to JIS K7210, Condition 4) and a melting point of 130 ° C is used as a low melting component and a polypropylene (PP) is used as the low melting component. 35 with an MFR of 4 (according to JIS K7210, Condition 14) and a melting point of 160 ° C. PE and PP are separately added a flame retardant (decabromodiphenyloxide) which has passed a particular sieve as indicated in the table shown below in certain

DK 155803B

- 8 - in relation to PE and PP respectively as indicated in the table and Sb20-j in half of the respective quantities of the fire-retardant. Component spinning is performed in the component ratio 1: 1 at a spinning temperature 5 on the PE side of 230 ° C and on the PP side of 300 ° C to obtain unstretched composite filaments lying side by side and having cross-sectional circumference ratios for The PE component of 78-85%. These filaments are stretched to 4 times the original length and cut to obtain staple fibers of 18 d / f (denier per

10 filament (x 64 mm) which is then carded to produce a sheet of 250 g / m2.

This sheet is subjected to heat treatment at 140 ° C for 5 minutes to obtain a sheet of non-woven fabric of 15 mm thickness, partially glued to the PE side. This sheet is cooled 15 in a dryer for 3-4 hours, then the combustion test is performed according to the above JIS method to measure the time when a flame (seconds) is still present and the

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charred area (cm). Furthermore, the same sheet of nonwoven fabric is subjected to the above combustion test according to the match method. The results of the mixture of the fire retardants, the spinning test and the combustion tests are shown in the table.

When Examples 1 and 2 are compared with Comparative Examples 1 and 2, and when Example 3 is compared with Comparative Examples 3 and 4, even though the content of flame retardant in the fibers as a whole is the same, if the flame retardant is only present in an amount of less than 3% in one of the components, then the flame retardant effect is too low, and this is remarkable especially when assessed by the match method. Furthermore, if the flame retardant is present in an amount greater than 15% in one of the components, the life of the spinning nozzles becomes shorter and the number of fiber breaks increases. Therefore, such an amount is also undesirable.

Examples 4-5 and Comparative Examples 5-7

As a low melting component, an ethylene-vinyl acetate copolymer (E-YA) having a melting point of 110 ° C, a vinyl acetate content of 5% and an MFR of 25 (according to JIS K7210, Condition 2) is used, and as high melting component is used a polypropylene

DK 155803B

- 9 - arrow (PP) with an MFR of 4. A mixture of perchloropenta-cyclododecane as a fire retardant and Sb 2 O 2 in a 2: 1 ratio is added in a certain amount to PP, and a mixture of bis- (3,5-dibromo) -4: dibromopropyloxyphenyl) sulfone and Sb 2 O 5 in the 1.5: 1 ratio are added in a specified amount to E-VA as indicated in the table. The 1: 1 component ratio is spun at a temperature of the low melting component of 200 ° C and a temperature of the high melting component of 280 ° C to obtain unstretched filaments, which are then stretched to 4 times the original length and cut. for staple fibers (6 d / eg 64 mm) of the casing and core type and having a fiber cross-sectional ratio of the low melting component of 100%, and a sheet of nonwoven fabric thereof which is subjected to combustion -15 test as in Examples 1 and 2 to assess the fire retardant properties. The results are shown in the table.

By comparing Examples 4 and 5 with Comparative Examples 5 and 6, it is seen that if the particle size of the fire retardant exceeds 62 microns, the spinnability and fiber quality becomes too low, and if the spin temperature is equal to the decomposition temperature, the spinnability is and the fiber quality likewise too poor due to a developed gas. Furthermore, it can be seen from Comparative Example 7 that although the content of a fire retardant throughout the fiber is the same, it will appear that if the content of a fire retardant in one of the components is less than 3%, then the fire retardant effect is reduced .

Examples 6-7 and Comparative Examples 8-11

As a low melting component, a polyethylene 30 (MFR: 10) (PE) is used and as a high melting component a polypropylene (MFR: 8) (PP) is used. Mixtures of either tris- (2,3-dibromopropyl) phosphate, 1,2-dibromo-3-chloropropane or penta-dibromo monochlorocyclohexane as a fire retardant and Sb 2 O 3 in a 3: 1 ratio are added in a certain amount to PE, while a mixture 35 of ethylenediamine dihydrobromide and Sb 2 O 2 in an amount of 2: 1 in a given amount are added to PP as indicated in the table. Spinning is carried out at a temperature of the low melting component of 210 ° C and of the high melting component.

DK 155803B

- 10 - 300 ° C in a component ratio of 1: 1 to obtain unstretched filaments which are then stretched 4 times the original length and cut to obtain staple fibers with fibers lying side by side (3 d / e.g. 64 mm) and with a ratio of fiber cross-section to perimeter of the low melting component of 49-50%. A nonwoven fabric is prepared from the staple fibers as in Examples 1 and 2 to assess the fire retardant properties. The results are shown in the table.

As can be seen from these results, it is the case that where the fineness of the fibers is small, the particle size of the fire retardant has a great influence on the spinnability (see Comparative Examples 8 and 9); if a flame retardant is present in a component in an amount of 12% (less than 15%) (with the content of flame retardant in the whole fiber being 12%), then both the spinnability and the fiber quality are poor (see Comparative Example 11), and if a fire retardant having a decomposition temperature equal to the spinning temperature is used, spinning is generally impossible (see Comparative Example 10).

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Claims (4)

A fire retardant composite fiber comprising a high melting component fiber forming olefin polymer and a 5 olefin polymer having a minimum melting point of at least 10 ° C than the low melting component as low melting component and having a fire retardant agent in the respective components, characterized in that: each component contains 3-15% by weight of a fire retardant having a decomposition temperature of at least 100 ° C above the melting point of the respective components and having a particle size of 62 microns or less, the total amount of the respective amounts of the flame retardants contained in the composite fibers as a whole are 5-10% by weight. A fire retardant composite fiber according to claim 1, characterized in that the high melting component is polypropylene or a copolymer in the main consisting of propylene units and the low melting component is polyethylene or a copolymer in the main consisting of ethylene units, and that the flame retardants added to these components have a decomposition temperature of 270 ° C or more. A method of producing fire retardant composite fibers using a fiber-forming 25 olefin polymer as a high melting component and an olefin polymer having a minimum melting point of at least 10 ° C than the high melting component as a low melting component, mixing a fire retardant with the respective components and spinning of the molten components and stretching, 30. characterized by mixing a fire retardant with a decomposition temperature of at least 100 ° C above the melting point of the respective components and a particle size of 62 microns or less with the respective components to obtain an amount of fire-retardant of 3-15 weight-35 percent and to obtain a total amount of the respective amounts of the fire-retardant in the composite fibers - as a whole of 5-10 weight percent and melting them obtained components at a temperature lower than the respective decomposition temperatures thereof flame retardant in the respective components for spinning. Method according to claim 3, characterized in that the fire retardants added to the high melting component and to the low melting component are fire retardant organic halogen compounds having a decomposition temperature of 40 ° C or more above the respective spin. -the temperatures of the components. 15 20 25 30 35