FI75875C - Fire retardant component fibers and process for their preparation - Google Patents

Description

, 75875

Fire retardant connecting fibers and method of making them

Eligibility of external components and frameworks

The invention relates to fire-retaining connecting fibers and to a method for their production. In particular, the invention relates to polyolefin interconnecting fibers comprising two different types of polyolefin polymers having different melting points and having the same or different flame retardants separately in both of these higher and lower melting components.

Polyolefin composite fibers have good thermal bonding properties as well as physical and chemical properties, and are also light and inexpensive. For this reason, they have been used as a fibrous material for nonwovens for various applications. Thus, they are suitable as a material for thin products such as base fabric, hygienic products, napkins, pieces of paper, as well as thick products such as stuffed products, various blankets, filters, fibrous products, public works materials, etc. -20 fire retardant properties. Among the methods for making polyolefin fibers flame retardant, mention should first be made of a method in which a flame retardant is added to the polymers used as a raw material, followed by spinning. However, the addition of flame retardants to the greatest extent causes various problems such as deterioration of productivity and product quality, etc. and further problems of spinning time and stretching, e.g. fiber breakage, deterioration, rough surface formation of fiber, decrease of thermal gluing properties, etc. These problems are considerable in the case of fibers of size 6 d / f (d / f = denier / filament) or thinner, and especially in the case of composite fibers, where these problems occur in particular on the lower melt viscosity component side. In addition to the method mentioned above 2 75875, methods for coating fibers with a fire retardant or mixing the fire retardant with these fibers are known. In connection with these methods, it should be noted that since once-formed fibers are processed by post-processing, the processing steps are complicated, the quality varies greatly and the costs are high, so these methods are not suitable for practical application.

The inventors of this application have extensively studied 10 these problems and found that the higher melting and lower melting components of the composite fibers contain a fire retardant having a decomposition temperature at least 100 ° C higher than the melting points of the corresponding components and an additional particle size of 15 62 μM or smaller than this, it is possible to produce low denier composite fibers with good fire retardant properties and thermal gluability, in which a relatively large amount of refractory material is also mixed with the low-melting component of the fibers, in addition to which these fibers have good spinnability. Based on this, the inventors have come to the present invention.

The object of the invention is to provide polyolefin connecting fibers with even better fire-retaining properties, as well as a method for producing these fibers.

According to one feature of the invention, refractory connecting fibers are obtained which contain a polyolefin polymer suitable for molding into a fiber as a higher melting component and a polyolefin polymer having a melting point at least 10 ° C lower than the melting point of the higher melting component. Containing a flame retardant, the interconnecting fibers being characterized in that the respective components contain a flame retardant having a decomposition temperature of at least 100 ° C higher than the melting points of the corresponding components and a particle size of 62 μm or less, and 75875 3, and this substance is present in the corresponding components in the amount of 3 .. .15% by weight, and the amount of flame retardant contained in the size of the connecting fibers is 5 ··· ΊΟ% by weight.

According to another aspect of the invention, there is provided a method of making refractory composite fibers using a polyolefin polymer suitable for molding into a higher melting component, and a polyolefin polymer having a melting point at least 10 ° C lower than the melting point of the higher melting component. , by mixing the flame retardant with the corresponding components and subjecting the obtained components to melt-spinning and then stretching, this method being characterized by mixing a flame retardant having a decomposition temperature of at least 100 ° C above the melting points of the respective components, and having a particle size of 62 μm or less, so that a flame retardant is obtained in an amount of 3 to 15% by weight, and also such that the connecting fibers as a whole contain a total of 5 to 10% by weight of a flame retardant, followed by The components thus obtained are melted at a temperature lower than the corresponding decomposition temperatures of the flame retardants contained in the respective components, after which these components are spun together.

The invention will be described in detail below, it is questionable that various special properties can be associated with their shrinkage and adhesion properties, depending on the interconnection of the connecting components, and it is also possible to use the fibers in applications where these properties are required. The connecting fibers according to the invention also have different fields of application. It is particularly preferred to use either the "lateral type" or the "sheath and core type" so that the cross-sectional area of the lower melt component 35 may be 50% or greater so that the interconnecting fibers acquire their thermal adhesion properties under the lower melt component. In this case, the bond ratio (higher melting 75875 component / lower melting component) is preferably in the range 5 = 5 .... 3 = 7 »considering the thickness of the lower melting component in the fiber cross section.

The higher melting component is preferably polypropylene or copolymers containing mainly propylene from which fibers can be formed. The lower melting component is preferably polyethylene, copolymers of ethylene and vinyl acetate having a vinyl acetate content of, for example, 1 to 10% by weight, of which the abbreviation EVA, further their saponified products, and polyethylene j8 EVA will often be used in the following. or mixtures of saponified EVA.

The respective concentrations of the refractory component of the high-containing component and the low-containing component of the connecting fibers are preferably in the range of 3 to 15% by weight, and the amount of the flame retardant contained in the total connecting fibers is preferably 5 to 10% by weight. If the concentrations of the flame retardant are below the above-mentioned limits, the flame-retardant effect is small, and if the concentrations exceed the above-mentioned limits, it is difficult to spin the fibers so that they become difficult to manufacture and of poor quality.

As the flame retardants according to the invention, such substances known from the prior art can be used. Among them, organic halogen compounds are preferably used, as concrete preferred examples of which are decabromodiphenyl oxide (Decomposition temperature 350 ° C, temperatures in the following brackets are decomposition temperatures), perchloropentacyclododecane (650 ° C), dihydroxy hexabromobenzene (34-0 ° C), 2,2-bis- [N- (2,3-dibromopropoxy) -3,5- (3-bromophenyl) propane (270 ° C), tris- (2,3-dibromopropyl) ) phosphate (260 ° C), bis-η 3 -5-dichloro-N-dibromopropyloxyphenyl-7-sulfone (280 ° C), etc.

These flame retardants are also preferably used in admixture with Sb ^ O ^ m, in a ratio of flame retardant: Sb ^ O ^ m = 5: 1 ... 3 = 1.

The flame retardants used in the present invention have a particle size of 62 μm or less, preferably 53,758 μm or less. If the flame retardants contain particles larger than 62, this causes a deterioration in productivity or quality due to, for example, clogging of the spinning nozzle, rupture of the fibers during drawing, formation of a rough surface of the fibers, which reduces their thermal adhesion properties.

Flame retardants having a particle size of 62 μm or less can be obtained by sorting commercially available flame retardants by a known method using e.g. a precipitation method, a cyclone method, etc., or a simpler method so that they are sorted Through sieves according to the JIS ZeeOI standard (nominal diameter 62 or 53 μm).

The fire-retaining connecting fibers according to the invention can be produced by applying a known melt-connecting spinning method, and a previously known device can also be used as a spinning device. By way of example, a powdered polymer raw material mixed with a flame retardant is melted and injection-molded through a melt-injection molding press, and the melt thus obtained is passed through a temperature-controlled heating zone to heat the melt to a specified temperature. The melting of the polymer and the temperature control are carried out separately in different channels for each connecting component, and the corresponding connecting components, each with its own determined temperature, are fed in connection with the spinning nozzles through these holes, whereby they are spun together. According to the invention, a flame retardant is used for the corresponding connecting components, having a decomposition temperature of at least 100 ° C above the melting point of the components and preferably at least 4-0 ° C higher than the spinning temperature, so as to prevent the flame retardant from decomposing and running out during spinning. The unstretchable filemen-35s obtained by spinning are stretched in an optional ratio depending on the applications. Stretching is often done using a stretch ratio of 4 or greater. As the stretching temperature, temperatures ranging from the softening point of the melting component to a temperature 10 ° C lower than the melting point can be used, but the effect of the stretching temperature on the fire retention properties is small.

By means of the method according to the invention, it is possible to produce connecting fibers which contain a large amount of flame retardant, and whose denier is small, where the frequency of chaining of the fibers due to clogging of the spinning nozzles and replacement of the spinning nozzle is low.

The fire-retaining composite fibers according to the invention, in addition to their fire-retaining properties, also have a smooth surface and superior thermal adhesion properties, despite the large amount of fire-retaining material they contain.

The invention is further illustrated in the following by means of Examples and Comparative Examples. The following definitions and test methods are used in these examples:

Flame Retardant Particle Size: This refers to the nominal mesh size of the standard screens (JIS Z8801) used in sorting and refers to the largest particle size of the flame retardant.

Spinnability: This is classified as the number of breaks in the fibers per hour, o: once or less, 25 Δ: twice, x: three times or more

Spinneret life: This is classified as the length of the spinneret replacement interval.

o: 40 hours or more, A: 20 to 39 hours, x: less than 20 hours 30 Adhesion strength: The relative value of the adhesive bond between a nonwoven sample and its blank (the blank is a piece of non-woven fabric made in the same way as the sample, except that it does not contain any flame retardant).

35 o: more than 90%, Δ: 70 ... 90%, x: less than 70%

Rough surface: Examine 100 filaments under a microscope and count the number of coarse-grained filaments.

o: 2 filaments or less, A: 3 ·· »9 filaments- 75875 7 tia, x: 10 filaments or more.

Flame retardant content: Sb ^ O ^ a is considered as an additive other than flame retardants.

Flame retardants: 5 number name flash point Φ 2,2-bi s- / 4- (2,3-dibromopropoxy)

-3,5-dibromophenyl / propane 270 ° C

© bis- (3,3-dibromo-4-dibromopropyl-

oxyphenyl) sulfone 280 ° C

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

Decabromodiphenyl oxide 350 ° C

© perchloropentacyclododecane 650 ° C

© ethylenediamine dihydrobromide 355 ° C

© 1,2-dibromo-3-chloropropane 210 ° C

15 (8) pentadibromomonochlorocyclohexane 230 ° C

Combustion test (J1S method): method according to JIS L1091, Al (45 ° micro burner)

Burning test (match method):

The nonwoven web is cut into a test piece having a length of 3 cm and a width of 20 cm in the direction of the fibers. The body thus obtained is fixed so as to form an angle of 30 ° with the vertical and is brought into contact with the flame of the match at its lower end until the specimen ignites and the match has burned out, the lower end of the specimen burning and the flame rising and moving upwards from its lower end. just after the test piece has ignited, remove the match and measure the remaining burning time of the flame. A web with a burn time of 5 seconds or less is considered to have passed the test, while a longer time of 30 seconds is considered a failure in the test.

Examples 1 to 5 and Comparative Examples 1 to 4 m Polyethylene (PE) having a melt flow index (MFR) ratio of 20 (according to JIS K7210, condition 4) was used as the lower melting component, and melt -55 mp 130 ° C, and polypropylene (PP) having an MFR = 4 (according to JIS K7210 standard, condition 14) and a melting point of 160 ° C were used as the higher melting component. A flame retardant e 75875 (decabromodiphenyl oxide) which had passed through the screen indicated in the following table for the PE and FF components and an additional half of the corresponding flame retardant 5 was added separately to both PE and PP components. The spinneret was then spun in a ratio of 1: 1, with a spinning temperature of 230 ° C on the PE side and 300 ° C on the PP side, to obtain non-stretchable "lateral" splice filaments having a cross-sectional circumference of the PE component of 70. ..85% · These fila-10 filaments were stretched to four times their original length and cut into staple fibers of 18 d / f (denier per filament) x 64 mm. These filaments were then carded to give a web weighing 250 g / m 2.

This web was heat treated at 140 ° C for 5 minutes 15 to obtain a 15 mm thick nonwoven web partially glued on the PE side. This web was allowed to cool in an oven for 3 · * 4 hours, after which a combustion test was performed according to the JIS method described above to measure the burning time of the flame (in seconds) and to measure the carbonized area (in square centimeters). In addition, the above-mentioned combustion test according to the match method was performed on the same nonwoven web. The table shows the results obtained by mixing the flame retardants, as well as the results of the spinning test and the combustion tests. 25 Comparing Examples 1 and 2 to Comparative Examples 1 and 2 and Example 3 to Comparative Examples 3 and 4, it is found that although the amounts of fire retardant contained in the fibers as a whole are the same, if the fire retardant is less than 3% in the second 5 ° connecting component, the flame retardant effect is inferior, and this is considerable especially when judged by the match method. If the amount of flame retardant still contained in one of the connecting components is more than 15%, the service life of the spinning nozzle is shortened, and the frequency of breaking the fibers is increased, so that such an amount is also detrimental.

75875 9

Examples 4, 1a 5 and Comparative Examples 9 .. «7 A copolymer of ethylene and vinyl acetate (EVA) with a melting point of 110 ° C, a content of 5% of vinyl acetate component 5 and an MFR = 25 according to JIS K7210 was used as the lower melting component. Condition 2), and polypropylene (PP) having an MFR = 4 was used as the higher melting component. To the PP component was added a mixture of perchloropentacyclododecane and ^ 2 ^ 3! 8 in a ratio of 2: 1, and to the EVA-10 component was added a mixture of bis- (3,5-dibromo-4-dibromopropyloxyphenyl) sulfone and 8 ^ 2 ^ 3 in a ratio of 1.5: 1 in the amounts indicated in the table. Thereafter, the conjugation was performed at a ratio of 1: 1, with the lower melting component having a temperature of 200 ° C and the higher melting component having a temperature of 280 ° C. Thus, inextensible filaments were obtained, which were then stretched to four times their initial length and cut into sheath and core-type staple fibers (6 d / f x 64 mm) having a cross-sectional circumferential length of 100 of the elongest fusible component. A nonwoven fabric was made from these staple fibers, which was subjected to a combustion test as described in Examples 1 and 2 to evaluate the fire-retaining properties of the fabric. The results are shown in the table.

Comparing Examples 4 and 5 to Comparative Examples 5 and 6, it can be seen that if the particle size of the flame retardant is more than 62, the spinnability and fiber quality deteriorate, and if the spinning temperature is the same as the Decomposition temperature of the flame retardant, the spinnability and fiber quality also deteriorate. due to evolving gas. It can be further seen from Comparative Example 30 7 that although the amounts of flame retardant in the fibers as a whole are the same, if the amount of flame retardant contained in the second component is less than 3%, the flame retardant effect deteriorates. Examples 6 and 7 and Comparative Examples 8 to 11 35 Polyethylene (PE) having an MFR = 10 was used as the lower melting component, and polypropylene (PP) having an MFR = 8 was used as the higher melting component. A fire retardant was added to the PE component. A mixture of tris- (2,3-dibromopropyl) phosphate, 1,2-dibromo-3-chloropropane or pentadibromo monochlorocyclohexane, and Sb ^ O ^ a to such an extent that the flame retardant and The ratio of SbpO 2 was 3: 1, while a mixture of ethylenediamine dihydrobromide and Sb 2 O 2 was added to the 5 PP components in a ratio of 2: 1 in the amounts indicated in the table. The spinning was then performed in a 1: 1 ratio, with the temperature being 210 ° C on the lower side of the fusible component and 300 ° C on the higher side of the fusible component. Thus, inextensible filaments were obtained, which were then stretched to four times their original length and cut into staple fibers which were "lateral" connecting fibers (3 d / fx 64 mm) with a 15% circumference of the lower melting component of 49-50%. the staple fibers were made into a nonwoven web as described in Examples 1 and 2 to evaluate the fire retaining properties. The results are shown in the table.

As can be seen from these results, in the case where the denier of the fibers is low, the particle size of the flame retardant has a large effect on the spinnability (see Comparative Examples 8 and 9) · If the flame retardant is 12%, i.e. less than 15%, the content of the flame retardant in the total amount of 25 fibers is 12%) are both spinnability and the quality of the fibers are both of low value (see Comparative Example 11). If a flame retardant having a decomposition temperature equal to the spinning temperature is used, spinning is quite impossible (see Comparative Example 10).

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Claims (4)

1. Fire retardant (Component containing as higher melting component a fiber forming polyolefin polymer and as lower melting component a polyolefin polymer whose melting point is at least 10 ° C lower than the higher melting component melting point, respectively). components contain a fire retardant, characterized in that each component contains a fire retardant having a decomposition temperature at least 100 ° C higher than the melting points of respective components, and also having a particle size of 62 µm or less, in a quantity of 3 - 15% by weight, and the total amounts of elastomeric substance which is entirely included in the component fibers is 5 ·· »10% by weight. 2. Elastomeric component fibers »according to claim 1, characterized in that said higher melting component is polypropylene or a copolymer which mainly contains propylene, and that the lower melting component is polyethylene or a copolymer which contains mainly ethylene and To these components, one or more fire retardants having a decomposition temperature of 270 ° C or higher were added. 5. A process for producing fire retardant component fibers by using a fiber forming polyolefin polymer as a higher melting component, and as the lower melting component a polyolefin polymer, the melting point of which is at least 10 ° C lower than the higher melting component melting point, mixing a fire retardant component. respective components and with the resultant components performs a composite melt spinning and then an elongation, characterized in that mixing with respective components is an fire retardant having a decomposition temperature at least 100 ° C higher than the melting points of each component, and having a particle size of 62 µm or less, said to be