DE2253976C2 - Process for making cellulose-containing fiber materials flame-resistant - Google Patents

Description

characterized in that the material is cooled prior to treatment with ammonia.

2. The method according to claim 1, characterized in that the impregnated material after the heating step is kept at room temperature for at least 1 minute.

3. Process according to claims 1 and 2, characterized in that the cooling of the in the process stage b) heated material is carried out by spraying with water.

The invention relates to a method for making cellulose-containing fiber materials flame-resistant.

The treatment of cellulosic fiber materials to give them fire resistance was Much effort has been made and many such methods have been proposed. However, they own most, if not all, of these known methods have disadvantages and are therefore unsatisfactory.

As discussed in US Pat. No. 3,236,676, many of the known processes have tetrakis (hydroxymethyl) phosphonium condensation products are used to impart the flame resistance to the cellulose materials, the disadvantage that the phosphonium compound shows the tendency while to migrate to the surface of the material during the hardening stage.

Another disadvantage of the known methods is the undesirable effects that the flame-resistant Chemicals affect the tensile properties of the treated materials.

In US-PS 32 36 676 a process is described in which a phosphonium compound on the cellulose material! is fixed and treated with ammonia. The method described is that the Cellulose materials are impregnated with a solution of Tetrakis-OiydroxymethyO-phosphonium salt, which has a pH in the range of 3 to 9.5. The material is allowed to dry between 100 and 180 ° C Material and heated to fix the phosphonium salt on the fiber, and then the heat-treated Material treated with ammonia to harden the phosphonium salt on the material. This method, which is generally successful in imparting flame resistance to cellulosic fiber materials, has the disadvantage that a heat setting step is required. Requires an additional process step additional time and more capital! and often brings with it a softening or crumbling with it or causes the physical character of the cellulosic material is deteriorated.

From US-PS 3607 356 a method for flame retarding cellulose-containing materials is known in which a) the cellulose-containing material with a tetrakis (hydror.ymethyl) phosphonium compound is impregnated, b) the impregnated material is dried without the phosphonium compound thereon to fix, and c) the material is then treated with ammonia for fixation. This procedure avoids although the additional heat setting stage; However, this does not result in sufficient fixation of the resin the cellulosic material.

The present invention is based on the object of a method for flame retarding cellulose containing fiber materials to provide that the physical properties of the treated material is not changed and is feasible in a simple and economical way.

The subject matter of the invention is a process for making cellulose-containing fiber material ion flame-resistant by

a) Impregnation of the cellulose-containing fiber material with an aqueous composition which has a Contains tetrakis (hydroxymethyl) phosphonium compound or a partially neutralized derivative thereof,

b) heating the impregnated material without fixing the phosphonium compound thereon and

c) treating the material with gaseous ammonia and / or mixtures of gaseous ammonia and water vapor in order to produce an insoluble polymer which is formed from the phosphonium compound and ammonia on and in the cellulose-containing fiber material,

characterized in that the material is cooled prior to treatment with ammonia. '

Preferably the impregnated material is left at room temperature for at least 1 minute after the heating step held. The material heated in process step b) is preferably cooled by Spraying with water.

According to the invention, cellulose-containing fiber material is impregnated with a solution, the tetrakls (hydroxymethyl) phosphonium chloride or contains a partially neutralized derivative thereof, e.g. B. Tetrakis (hydroxymethyl) phosphonium chloride, in some cases with 70 to 90% of the stoichlometric amount of alkali metal hydroxide was neutralized. The impregnated material is heated to at least partially dry it,

without fixing the phosphonium compound to it, and then after cooling the heated material the phosphonium compound is hardened on the material by converting this gaseous ammonia, possibly in Presence of water vapor.

The method according to the invention is suitable for regenerating cellulose-containing fiber materials such as cotton Cellulose, blends of these textile fibers with synthetic fibers such as polyester-cotton blends, To give wood, paper fire resistance or a fire-proof character.

A preferred way of carrying out the process according to the invention consists in using a cotton cloth with an aqueous solution of 20 to 40 wt .-% tetrakis-diydroxymethyO-phosphonium chloride, which partially was neutralized with 70 to 90 »of the stoichiometric amount of alkali metal hydroxide, wlogs. The pounded Cloth that contains 25 to 150 * its weight in padding liquid is at least partially dried, preferably to a moisture retention of 5 to 25% without fixation of the phosphonium compound the cloth; the partially dried cloth is cooled and then gaseous ammonia, preferably in Presence of water vapor, exposed to the phosphonium compound on the cloth or on the cloth to fix, and at the same time these fire-resistant properties that are resistant to repeated washing are to lend. The treated cloth is preferably mixed with an aqueous solution of an oxidizing agent such as hydrogen peroxide, sodium perborate to remove discoloration and odor after treatment removed from the treated material.

The padding solution used can simply be an aqueous solution of tetrakis (hydroxymethyl) phosphonium chloride be. However, these solutions have a pH of about 1, and this may be over against treated textile material can be harmful. Preferably, the solution is partially adjusted to a pH value Range from 5 to 5 pounds neutralized. Alkaline materials such as sodium or potassium hydroxide, anhydrous soda, organic amines such as triethanolamine, triethylamine can be used to reduce the pH of the Kiotz- or impregnation liquid.

It is preferred to dry the impregnated cloth to remove at least a portion of the aqueous liquid or Solution to remove. This drying stage can be done in a drying oven by padding the The cloth is passed over heated belts or sleeves or the cloth is ironed and by similar measures. Preferably the impregnated material is dried to 5 to 25% by weight moisture retention. It; became found that this partial drying of the impregnated material did not result in any noticeable fixation Amounts of phosphonium compound on the fiber. It was also found that the impregnated material essentially completely at a moderate temperature of 93 ° C with no fixation of the Phosphonium compound can be dried. After that, the dried material is cooled before it is used treated with ammonia to fix the phosphonium compound.

It has been found that, after the padded or impregnated material has dried, it is important that To cool the material before passing it into the curing device. Little or no fixation of the Resin on the material during the '-'hardening, if the dried, impregnated material immediately hardens after removal from the dryer or when the dried material is in hot In the same state, if you put the material between layers of insulating cloth and the resin on the material hardens. It is therefore an essential step in the process of the invention to remove the material to cool from the dryer, preferably for at least 1 minute at room temperature. That Cooling of the hot, dried material can be achieved by keeping the material at room temperature in the air or through a cool box or a cold device over cold jugs or cold baths or sprayed it with water.

Salts other than tetrakis (hydroxymethyl) phosphoniam chloride can be used. You can do that use the appropriate acetate, bromide, sulfate, phosphate. The chloride is preferred as it is generally is commercially available.

The following examples illustrate the invention without, however, restricting it. Unless otherwise stated, parts and percentages are given by weight and temperatures by ° C.

Test series to explain the effects of drying and / or heating:

A 40% aqueous solution of tetrakis (hydroxymethyl) phosphonium chloride was partially; neutralized with approximately 80% of the theoretical amount of sodium hydroxide. The resulting solution was used to impregnate samples of 108 g / m ² cotton flannel. The impregnated cloth was then heated in a 93 ° C oven during the periods indicated in the table below. The partially dried cloth was extracted with water. A sample of the extract was evaporated to dryness and the residue was analyzed.

About 5 parts of the extract were mixed with 50 parts of methanol and the mixture was mixed with Ammonia gassed until no further reaction could be recognized. The precipitate formed was through Filtration separated, dried and analyzed. The results obtained are shown in the table below.

Table I.

Sample 1 Sample 2 Sample 3

82.2 parts 78.7 parts 79.6 parts 7.5 1.75 0 41.9 parts 39.5 parts 40.9 parts 24.9 24.9 23.7 6.7 6.9 6.9 16.6 16.0 16.0 11.3 13.3 11.1 5.1 5.1 5.2 2.7 2.9 2.7 211-212 211-212 211-212 32.2 34.4 32.9 (38.4) 6.2 6.7 6.2 (7.2) 13.7 14.7 13.9 (14.3) 23.9 25.7 23.7 (27.1)

Flannel weight 39.6 parts 37.3 parts 38.5 parts

Weight of the sample after impregnation
Drying time at 93 ° C (minutes)
Weight of the aqueous extract
Analysis of the extracted solid

carbon

hydrogen

phosphorus

chlorine

Weight of the extracted extract sample
Weight of precipitation
Fp of precipitation ( ⁰ C)
Analysis of precipitation

carbon

hydrogen
nitrogen

phosphorus

The values in brackets are analytical results of a product obtained by adding ammonia passes into an aqueous solution of tetrakis (hydroxymethyl) phosphonium chloride.

These results show that drying and / or heating the phosphonium compound on the cloth this compound is not fixed or chemically changed during the process.

example 1

This example shows the effect of cows; H. the temperature of the impregnated cloth at the time the hardening to the amount of fixed resin on the cloth.

An aqueous solution containing 27.5% tetrakis (hydroxymethyl) phosphonium chloride was approximately 85% of the stoichiometric amount of sodium hydroxide was neutralized, with 27.5% being partially neutralized

Samples received. Six samples of 108 g / m ² cotton flannel were impregnated with this solution to a moisture absorption of approximately 90 to 95%. The impregnated cloth samples were dried at 93 ° C for various times and then exposed to gaseous ammonia to cure the resin. The treated material was then cleaned in an aqueous alkali bath containing sodium perborate and dried. Two of the samples (1 and 2) were treated directly from the dryer with a relatively short, ie approximately 2 to 3 minute cooling time. A sample (3) was removed from the dryer, held in air for about 1 minute and then passed over a perforated tube which emitted steam and then exposed to ammonia gas. A sample (4) was passed twice over the perforated tube which emitted steam. Two samples (5 and 6) were removed from the dryer and kept warm with a hot iron for about 5 minutes and immediately placed between two layers of insulation cloth to minimize cooling and then exposed to ammonia gas. The weight or amount of cured resin attached to the cloth samples was determined in each case. Treated samples were tested according to AATCC Standard Test Method 34-1966 initially, after 10 standard house washes, and after 25 such washes to evaluate fire resistance.
The results obtained in these experiments are in d ~? Table II listed below.

Table II

sample 1 2 3 4th 5 6th % THPC 27.5 27.5 27.5 27.5 27.5 27.5 % Moisture absorption 91 95 96 94 95 96 Drying time at 93 ° C (min) 2 6th 6 ¹ ) 6 · ') 6 ³ ) % of resin in the cured sample 13.2 16.0 14.5 11.6 0 0 first simmering, cm 10.9 6.4 9.4 12.7 V 4) V 10 household washes 13.0 12.7 12.7 15.7 V V 25 household washes 10.2 10.7 11.7 12.7 V V

'), Vaporized by passing once through a perforated tube

² ) vaporized by passing twice through a perforated tube

³ I heated in an iron and kept warm

*) Incineration

These results goats that heating the dried sheet without cooling it down prior to curing entails brings that no resin sticks. The results also show that the hardening of the partially dried Is equivalent to cloth after cooling with or without steaming.

Example 2

In the same way as described above in Example 1, samples of 108 g / m ^{2 of} cotton flannel were impregnated with a 27.5% strength aqueous solution of partially neutralized tetrakis (hydroxymethyl) phosphonium chloride. The samples were then heated at 93 ° C. for the times indicated in the table below, after which the partially dried samples were treated as follows.

A sample (1) was removed from the dryer, held in air for approximately 1 minute and exposed to gaseous ammonia.

A sample (2) was taken from the dryer, held in air for approximately 1 minute, immediately heated in a flat bed press, removed therefrom, between two layers of insulated cloth placed in order to avoid cooling and then exposed to the gaseous ammonia.

A sample (3) was taken from the drying device, held in air for at least 1 minute, passed through a perforated tube that gave off steam and then exposed to gaseous ammonia.

A sample (4) was removed from the dryer, passed twice over the perforated steam tube and then exposed to gaseous ammonia.

A sample (5) was removed from the dryer, placed in a flat bed press, sprayed with a fine spray of water and then exposed to gaseous ammonia. Four samples (6 to 9) were removed from the dryer while held at room temperature for approximately 16 hours and then exposed to gaseous ammonia.

All samples were weighed to determine the amount of resin deposited or added, and then their fire resistance was evaluated. The results of these series tests are in summarized below in Table III.

Table III

Sample 12 3 4 56789

% partially neutralized THPC 27.5 27.5% moisture absorption
Drying time at 93 ° C (min)
treatment

% resin absorbed
initial scorching, cm

10 house washes
25 houses

91

93 8

27.5
93

27.5 27.5 27.5 27.5 27.5

97

92

91

90
10

89

no hot one-two-two-hot storage for 16 hours.

Hardening and hardening

Steam transfer spraying

11.2 2.0 9.9 13.7 11.3 10.7 9.0 11.4 13.0

50.8 burn 9.1 7.6 10.2 10.4 9.6! 3.0 9.6 ^ω

10.7 Burn-10.2 8.1 9.6 14.7 11.7 14.0 12.7

9.6 Burn 9.4 10.7 9.6 12.7 9.4 13.0 12.7

tion

These results show that resin impregnated on hot, damp cloth cures better than resin that is

Impregnated on a hot, dry cloth It is better that resin impregnated on a cold, damp cloth hardens as a resin that is impregnated on a hot, damp cloth and that spraying with a water mist, Steam or store the resin on a hot, dry cloth substrate during an extended tent reactivated.

Example 3

an aqueous solution containing 22.5% partially neutralized (8596) TetrakMhydroxymethyD-phosphonium chloride ίο was used ^{to impregnate three samples of 108 g / m 2} and 128 g cotton flannel, respectively. The moisture uptake of the three samples was 92.5, 91.7 and 94.5%.

A sample was kept at room temperature for 16 hours, and the amount of resin picked up after treatment with ammonia gas was 15.7%. The cloth sample was examined for its fire resistance and was found to have an initial scorch of 9.4 cm.
The other two samples were heated to 93 ° C for 1.5 and 3 minutes, and the partially dried cloth was hung in air at room temperature for about 16 hours and then cured.

The resin uptake for these two samples was 14.6 and 17.3 percent. Both samples were fire resistant and showed an initial scorch at 10.7 cm and 9.6 cm.

These tests show that the impregnated material even after a storage tent according to the tell Drying can be cured without affecting the fire-resistant properties.

Example 4

An aqueous solution containing 22.5% partially neutralized tetrakis (hydroxymethyl) phosphonium chloride was used ^{to impregnate samples of 108 g / m 2} cotton flannel. The samples show an uptake between 85 and 95%.

The samples (3) were partially for 1 minute at 93 ° C, for 1.75 minutes at 93 ° C and during Dried for 1.75 minutes at 121 ° C. Resin uptake was determined to be 16.5, 17.4 and 17.5 percent. the partially dried samples were cooled slightly and then a mixture of gaseous ammonia and exposed to moist steam. By passing the samples through a perforated tube, the one Emission of steam and ammonia. The hardened samples were placed in an aqueous alkali bath, containing sodium perborate, washed.

Each of the cured resin-impregnated cloth samples was tested for fire resistance, and man found that they had equivalent fire resistance which was permanent and that the samples to that Stewed were about the same resistance even after 50 helmet washes.

For comparison, a cotton flannel sample was impregnated with an aqueous solution as described above and the impregnated cloth was dried at 93 ° C for 1 minute. The heated cloth was then subjected to a mixture of ammonia gas and air to cure the resin on the cloth. the Resin uptake in this case was 15.6%. The fire retardant properties of the treated cloth were essentially the same as that of the above samples. However, the fire resistance was after 50 helmet washes this sample was significantly worse compared to the above samples, and the scorching increased by approximately twice as much, based on the original scorching length (9.9 cm at the beginning; after 50 house washes 16.8 cm).

These results show the permanence of the fire retardant nature of the material when refrigerated and hardened with gaseous ammonia in the presence of water vapor.

Claims (1)

Patent claims: 1. Process for making cellulose-containing fiber materials flame-resistant by a) Impregnation of the cellulose-containing fiber material with an aqueous composition which has a Tetrakis (hydroxymethyl) phosphonium compound or a partially neutralized derivative thereof contains, b) heating the impregnated material without fixing the phosphonium compound thereon and c) Treating the material with gaseous ammonia and / or mixtures of gaseous ammonia and water vapor to produce an insoluble polymer derived from the phosphonium compound and ammonia is formed on and in the cellulose-containing fiber material,