DE2253976A1 - FIRE-RESISTANT CELLULOSE MATERIALS - Google Patents

Description

Dipl.-Ing. H. Weickmann, Dipl.-Phys. Dr K. Fincke WTMY Dipl.-Ing. F. A. Weickmann, Diel. * Chem. B. Huber

'8 MUNICH 86, DEN

3051 PO Box 860 820

MÖHLSTRASSE 22, CALL NUMBER 98 39 21/22

Hooker Chemical Corporation, Niagara Falls, N.Y. 14302 / USA

Refractory cellulosic materials

The invention relates to a method to cellulosic materials To impart fire resistance. According to the method of the invention, the cellulosic material is with a aqueous solution of a tetrakis (hydroxymethyl) phosphonium compound, preferably partially neutralized tetrakis (hydroxymethyl) phosphonium chloride, impregnated, the impregnated material at least partially dried, i.e. on about 5 to 25% by weight moisture retention without the phosphonium compound being fixed to the material. That partially dried material is then cooled and treated with dry ammonia gas, optionally in the presence from water vapor, whereby the phosphonium compound is hardened on the material and this makes it fire-resistant or resistant to fire. retains its fire-resistant character.

The invention relates to a method for producing flame-retardant cellulose-containing materials. The invention relates in particular to a method for incorporating a polymer containing phosphorus into cellulosic materials and get up to it.

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The treatment of cellulosic materials to this To give fire resistance has been the subject of many efforts, and many such methods have been proposed. However, most if not all of these have known ones Process disadvantages and are therefore unsatisfactory.

As discussed in U.S. Patent 3,236,676 many of the known processes in which tetrakis (hydroxymethyl) phosphonium condensation products used to give the cellulosic materials flame resistance, the disadvantage that the phosphonium compound has the tendency shows migrating to the surface of the material during the curing stage.

Another disadvantage of the known methods is that they are undesirable Effects that the flame retardant chemicals have on the tensile properties of the treated materials.

US Pat. No. 3,236,676 describes a method in which a phosphonium compound prior to hardening with an agent such as ammonia is fixed on the cellulosic material. The method described is that the Cellulosic materials with a solution of tetrakis (hydroxymethyl) phosphonium salt are impregnated, which has a pH value in the range from 3 to 9 * 5. The material is between 100 and 180 C to dry the material and to fix the phosphonium salt to the fiber and then heated treating the heat treated material with ammonia to harden the phosphonium salt on the material. This method, which is generally successful in imparting flame resistance to cellulosic materials, has the disadvantage that a heat setting step is required. An additional Process step requires additional time and more capital and often entails a calibration or degradation or causes the physical character of the cellulosic material to be deteriorated.

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The present invention is therefore based on the object of developing a method for cellulosic materials To impart fire resistance without otherwise altering the physical properties of the material being treated. The invention relates to a simple, economical and effective process for the treatment of cellulose-containing substances Materials containing aqueous solutions of tetrakis (hydroxymethyl) phosphonium compounds, to make these materials fire-resistant or flame-proof *

According to the invention cellulose-containing material is impregnated with a solution, the tetrakis (hydroxymethyl) phosphonium chloride or contains a partially neutralized derivative thereof. 'The impregnated material is heated to at least it partially dry without fixation of the phosphonium compound to it and then after cooling the heated material the phosphonium compound is hardened on the material by adding this gaseous ammonia, optionally in the presence from water vapor.

The inventive method is suitable for cellulose-containing materials such as cotton, regenerated cellulose, mixtures these textile fibers with synthetic fibers such as polyester-cotton blends, wood, paper, etc. to give a fireproof character.

A preferred way of carrying out the process according to the invention is that a cotton cloth with an aqueous solution of about 20 to about 40 wt Alkali hydroxide has been neutralized to pad. The padded cloth to 150% contains about 25 of its weight of padding liquor, is at least partially dried, preferably to a moisture retention of about 5 to un _r

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about 25% without fixation of the phosphonium compound on the cloth; the partially dried cloth is cooled and then exposed to gaseous ammonia, preferably in the presence of water vapor, in order to fix the phosphonium compound on the cloth, thereby imparting fire-resistant properties which are resistant to repeated washing. The treated cloth is preferably washed with an aqueous solution of an oxidizing agent such as hydrogen peroxide, sodium perborate, etc. in order to remove discoloration and odor from the treated material after the treatment.

The pad solution used can simply be an aqueous solution of tetrakis (hydroxymethyl) phosphonium chloride. These However, solutions have a pH of approximately 1 and this can be detrimental to the textile material to be treated be. Preferably the solution is partially neutralized to a pH in the range of about 5 to 6.5. Alkaline materials such as sodium or potassium hydroxides, anhydrous soda, organic amines such as triethanolamine, triethylamine Among other things, can be used to adjust the pH value of the padding or impregnation fluid.

It is preferred to dry the impregnated cloth by at least to remove some of the aqueous liquid or solution. This drying stage can be done in a drying oven, by passing the padded cloth over heated tapes or cans or by ironing the cloth and through similar measures. Preferably the impregnated material is dried to 5 to 25% by weight moisture retention. It was found that this partial drying of the impregnated material did not cause any noticeable fixation Amount of phosphonium compound on the fiber. This was also found to impregnate Material essentially completely at a moderate temperature

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temperature of about 93 ° C (20O ⁰ F) can be dried without fixation of the phosphonium compound. The dried material is then cooled by rewetting before treating it with ammonia in order to fix the phosphonium compound.

It has been found that, after the padded or impregnated material has dried, it is important to close the material cool before passing it into the curing device. It was found that there was little or no fixation of the resin occurs on the material during curing when the dried, impregnated material is removed immediately after removal curing from the dryer or leaving the dried material in a hot state when the material between layers of insulating cloth and the resin hardens on the material. It is therefore an essential stage of the process according to the invention, the Material after removal from the dryer for at least about, 1 minute, and preferably to cool longer. Cooling of the hot, dried material can be achieved by keeping the material at room temperature holds in the air or passes through a cool box or a cold device over cold jugs or cold belts or sprayed it with water or similar.

Other salts except tetrakis (hydrox3naethyl) phosphonium chloride can be used. You can use the appropriate acetate, bromide, sulfate, phosphate and other compounds. That Chloride is preferred because it is generally commercially available.

The following examples illustrate the invention without, however Restrict / Unless otherwise specified, parts and percentages are by weight and temperatures

0, O _x

C (F) indicated. .

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example 1

A 40% strength aqueous solution of tetrakis (hydroxymethyl) phosphonium chloride was partially neutralized with about 80% of the theoretical amount of sodium hydroxide. The resulting solution was used to impregnate samples of 108 g / m (4.5 ounce per square yard) cotton flannel. The impregnated cloth was then heated in a 93 C oven for the times 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
mixed and the mixture was gassed with ammonia until
no further reaction was recognizable. The educated
Precipitate was separated by filtration, dried
and analyzed. The results obtained are shown in the table below.

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Table I. Sample 2 Sample 3 Sample 1 37.3 parts 38.5 parts Weight of the flannel 39.6 parts 4th
78.7 79.6 Weight of the sample
impregnation 82.2 parts 1.75. Ö Drying time b. 93 ° C
Minutes (200 ⁰ F) 7.5 39.5 40.9 Weight of aqueous
Extract 41.9 parts Analysis of extract
th solid 24.9 23.7 carbon 24.9 6.9 6.9 hydrogen 6.7 16.0 16.0 phosphorus 16.6 13.3 11.1 chlorine 11.3 5.1 5.2 Weight taken
nen extract sample 5.1 2.9 2.7 Weight of the low
blow 2.7 211-212 211-212 Fp of precipitation
° C 211-212 Analysis d.Nieder
blow 34 ₉ 4 32.9 (38.4) carbon 32.2 6.7 6.2 (7.2) hydrogen 6.2 14.7 13.9 (14.3) nitrogen 13.7 25.7 23.7 (27.1) phosphorus 23.9

The values in parentheses are analytical results of a product obtained by adding ammonia to an aqueous solution derived from tetrakis (hydroxymethyl) phosphonium chloride.

These results indicate that drying and / or heating the phosphonium compound on the cloth will remove this compound not fixed or chemically changed in the process.

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Example 2 / ',

This example shows the effect of cooling, i.e. the temperature of the impregnated cloth at the time of curing to the amount of the fixed resin on the cloth.

An aqueous solution containing 27.5% tetrakis (hydroxymethyl) phosphonium chloride was neutralized with approximately 85% of the stoichiometric amount of sodium hydroxide to give 27.5 % partially neutralized samples. Samples of 108 g / m (4.5 ounce per square yard) cotton flannel were impregnated with this solution to a moisture pick-up of approximately 90 to 95%. The impregnated cloth samples were dried at 93 ° C (200 ° F) 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 were treated directly from the dryer with a relatively short, i.e. approximately 2 to 3 minute cooling time. and then exposed to ammonia gas. A sample was passed twice over the perforated tube which emitted steam. Two samples were removed from the dryer and held warm with a hot iron for approximately 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.

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The results obtained in these experiments are shown in FIG listed below in Table II.

Sample 1 Tabel II 4th 1 27 27.5 2 1 27.5 27.5 96 % THPC 91 27.5 27.5 94 95 _6th % Moisture
recording 2 95 96 6 ² 6 *. 0 Drying time b.
93 ° C (200 ° F) 13.2 6th 6 ¹ 11.6. 0 • ν % of resin id
hardened sample 10.9
(4.3) 16.0 14.5 12.7
(5.0) V ⁴ V first through
stew (initial
Char), cm (inch) 13.0
(5.1) 6.4
(2.5) 9.4
(3.7) 15.7
(6.2) V V 10 household
to wash 10.2
(4! O) 12.7
(5.0) 12.7
(5.0) 12.7
(5Jo) V 25 household 10.7
(4 | 2) 11.7
(4 ', 6)

Legend: steamed by going once over a perforated

Tube conducts 2

vaporized by passing twice through a perforated tube

- * heated in an iron and kept warm / j.

combustion

These results show that heating the dried sheet without cooling before curing does not entail any Resin sticks. The results also show that hardening of the partially dried cloth after cooling with or is equivalent without steaming.

Example 3

Samples of 108 g / m (4.5 ounce per square yard) cotton flannel were made in the same manner as described in Example 2 above with a 27.5% aqueous solution of partly new

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tralized tetrakis (hydroxymethyl) phosphonium chloride impregnated. The samples were then kept at 93 ⁰ C (200 F) during the following. The times indicated in the table were heated, after which the partially dried samples were treated as follows.

A sample was taken from the dryer, in air held for about 1 minute and exposed to ammonia gas.

A sample was taken from the dryer, held in air for approximately 1 minute, immediately in one Flat bed press (flat bed press) heated, removed from it, placed between two layers of insulated cloth to make a Avoid cooling down and then exposed to the gaseous ammonia.

A sample was taken from the dryer, held in air for at least 1 minute, via a perforated Tube that gave off steam, then exposed to gaseous ammonia.

A sample was removed from the dryer, passed twice over the perforated steam tube and then in gaseous form Exposed to ammonia.

A sample was removed from the dryer, placed in a flat bed press, with a fine Sprayed water spray and then exposed to gaseous ammonia. Four samples were removed from the dryer, held at room temperature for approximately 16 hours and then exposed to ammonia gas.

All samples were weighed to determine the amount of resin that deposited was or added v / ar, to determine ur.d thin was hers Fire resistance rated. The results of these series tests are summarized in Table III below.

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O CD OO

σ cn ο

sample

% partially neutralized THPC

% Moisture absorption

Dry time at 93 ° C (20O ⁰ F) / min treatment

% resin absorbed

initial scorching, cm (in.)

10 house washes

25 house washes

27.5 91

no

table III 3 4

27.5 93 -

27.5

92

27.5
97

8 6 6 6

hot hardening one time, two hot times, one time hardening Steam transfer spraying

11.2 2.0

50.8 combustion (20.0)

10.7 "(4j2)

13.7

7.6
(3.0)

SU) U)

11.3

10.2
(4.0)

27.5 27.5 27.5 27.5

92

91

90 89

6 6 10 2

Storage for 16 hours

10.7

10.4
(4.1)

12.7
(5 0)

9.0 11.4 13.0.

9.6 13.0 9.6 (3.8) (5.1) (3.8)

5 *, 5) (5jo)

13.0 12.7 (5 1) (5j0)

cn co co -j

These results show that resin impregnated on hot, damp cloth adheres better than resin impregnated on hot, damp cloth. Impregnated on dry cloth is that resin impregnated on cold, damp cloth hardens better than resin that is impregnated is impregnated on hot, damp cloth and that spraying with a water mist, steaming or storing during the resin on a hot, dry cloth subscrat for a longer period of time reactivated.

Example 4

An aqueous solution containing 22.5% partially neutralized (85/0 tetrakis-hydroxymethylI-phosphonium chloride) was used to impregnate three samples of a 108 g / m (4.5 ounce) or 128 g of cotton wool flannel. The moisture absorption of the three samples was 92.5ι, 91.7 and 94.5%.

A sample was stored at room temperature for 16 hours and the amount of resin picked up after the ammonia gas treatment was 15.7%. The cloth sample was was examined for fire resistance and was found to have an initial scorch of 9.4 cm (3.7 inches).

The other two samples were ^{heated to 93 °} C (200 ^° F) 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%. Both samples were fire resistant and showed an initial Scorch at 10.7 cm (4.2 inches) and 9 ^ 6 cm (3.8 inches).

These tests show that the impregnated material, even after a period of storage, after partial drying can be hardened without losing the fire-resistant properties affects v / earth.

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Example 5

An aqueous solution that partially neutralized 22.5% Contains tetrakis (hydroxymethyl) phosphonium chloride used to impregnate samples of 108 g / m (4.5 ounce) tree roll flannel. The samples showed an uptake between about 85 and 95%

The samples (three) were partially for 1 minute at 93 ° C (200 ⁰ P), for 1.75 minutes at 93 ° C (200 ⁰ P) and for 1.75 minutes at 121 ⁰ C (250 ° F) - dried. Resin uptake was determined to be 16.5, 17% and 17.5%. The partially dried samples were cooled slightly and then exposed to a mixture of gaseous ammonia and moist steam by passing the samples over a perforated tube, the one Mixture of steam and ammonia emitted * The cured samples were washed in an aqueous alkali bath containing sodium perborate.

Each of the cured resin-impregnated cloth samples was applied to their fire resistance was examined and it was found that they were possessed equivalent fire resistance which was permanent and that the samples were resistant to scorching even after 50 home washes were about equally resistant *

For comparison, a cotton flannel sample was impregnated with an aqueous solution as described above and the impregnated cloth was ^{searched for 1 minute at 93 ° ß (SOO 0} F). The heated cloth would then be subjected to gas and air, and the temperature on the cloth 2 & the resin absorption would be 15.6% * in this case; The fire-resistant properties of the treated cloth would be the same as those of the above samples if they were found to be the same as those of the samples above.

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3 Ö18 1 S / 1 Q @ Ö

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Braising increased by about double the original braising length (initially 9.9 cm (3 _f 9 ^ inches); after 50 house washes 16.8 cm (6.58 inches)).

These results show the permanence of the fire retardant character of the material when exposed to ammonia gas was cured in the presence of steam.

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Claims (9)

72 5 3 9 7 6-15 - claims 1. Process for the production of fire-resistant, Cellulose-containing materials, -characterized, that he a) a cellulose-containing material is impregnated with an aqueous composition which is a tetrakis (hydroxymethyl) phosphonium compound or contains a partially neutralized derivative thereof, b) the impregnated material is heated without fixing the phosphonium compound to it, c) the material cools, and d) treated the material with gaseous ammonia and / or mixtures of gaseous ammonia and water vapor, to produce a substantially insoluble polymer composed of the phosphonium compound and ammonia on and in the cellulose-containing material is formed. 2. The method according to claim 1, characterized in that the impregnated material is at least partially during the heating stage dries. 3. The method according to claim 2, characterized in that the impregnated material contains from 5 to 23% of impregnated moisture after the heating step. 4. The method according to claim 1, characterized in that the impregnated material at room temperature during held for at least 1 minute after the heating step. 5. The method according to claim 1, characterized in, that the cooled material is exposed to steam and gaseous ammonia. - 16 - 309819/10 6 0 225 ^ 976 6. The method according to claim 1, characterized in that the cooled material is exposed to gaseous ammonia. 7. The method according to claim 1, characterized in that that the heated material is cooled by spraying it with water and then exposed to gaseous ammonia, 8. The method according to claim 1, characterized in that that the phocphonium compound is tetrakis (hydroxymethyl) phosphonium chloride used. 9. The method according to claim 1, characterized in that the phosphonium compound is tetrakis (hydroxymethyl) phosphonium chloride used that with about 70 to about 90 ^ the stoichiometric amount of a caustic alkali neutralized, was. 309819/1060