CZ358597A3 - Process of bleaching fabrics - Google Patents

Abstract

The present invention relates to the bleaching of fabrics with a hypochlorite-containing composition. The well known prejudice against using hypochlorite bleaches to bleach synthetic fabrics because of the resulting fabric yellowing is addressed by the presence of silicate salts in the bleaching medium.

Description

Method of bleaching fabrics

Technical field

The present invention relates to bleaching fabrics with a bleaching composition comprising hypochlorite.

The prior art.

Bleaching agents are well known in the art. Geochlorine · bleaching agents based on hypochlorite · as a bleaching agent. they are preferred over oxygen bleaches, in particular for performance reasons, especially at lower temperatures. : "However, j ^; Some limitations of the benefits of hypochlorite agents are present. In particular it is. it is well known from consumers that hypochlorite can cause yellowing of bleached fabrics. This is particularly true of synthetic fabrics, and indeed there is a bias against the use of hypochlorite bleaches on synthetic fabrics as can be seen from the warnings. on commercially available hypochlorite bleaches; Also, many fabrics made of or containing synthetic fibers are marked as indivisible by the manufacturer. ^: -. . <· .... '

It is therefore an object of the present invention to solve the problem of synthetic yellowing. of fabrics while bleaching with hypochlorite bleach. · '. . ·. .

We have found that this problem can be effectively solved if the hypochlorite solutions used _; for bleaching 'synthetic' fabrics further comprising an effective amount of an alkali metal salt of silicate. It is believed that the presence of silicates in the solution plays a role in treating or preventing hypochlorite from affecting the brighteners that are located on the surface of the synthetic fabrics during their manufacture and / or when washing fabrics with laundry detergents which They contain brighteners, probably due to the regulation of metal impurities such as Cu, Fe, Ni and Co. In darkness

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For example, we have observed that the effect of preventing yellowing is associated with the presence of a brightener placed on the surface of the synthetic fabric. The present invention is very practical, since most modern synthetic fabrics have surface brighteners.

US 3,056,645 and US 3,030,171 disclose a method for bleaching fabrics which comprises hypochlorite-containing compositions. Silicates are mentioned as an optional component, and neither of these documents discusses the presence of brighteners on the fabric surface, nor the beneficial effect of silicate as the present invention; '. . ....

US 4,120,650 discloses a process for bleaching fabrics with a solution comprising anionic and nonionic surfactant, chlorine bleach and oxygen bleach under controlled conditions. Silicates are mentioned as an optional component and are described in this method. it can be used on synthetic fabrics. The presence of brighteners on fabrics has not been discussed.

US 2: 73.3,120 discloses a process for bleaching fabrics with hypochlorite in the presence of soap. Silica-n is mentioned as an optional component, and the document does not discuss synthetic fabrics and yellowing .....

US .1,931,245 describes a composition comprising. hypochlorite and silicate and its use for bleaching viscose fibers. . The silicate is said to protect the aluminum support used in the processes against corrosion.

EP 351,947 discloses a composition comprising hypochlorite and a brightener selected for stability in the composition. Silicates are mentioned as an optional component.

The co-pending European applications 93203153, 93870070.7, 942.02716 and 94870103 disclose compositions containing hypochlorite and silicon, but do not discuss their possible use on synthetic fabrics having brighteners placed on their surface. .

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SUMMARY OF THE INVENTION SUMMARY OF THE INVENTION

The present invention relates to a method for bleaching a synthetic fabric having a brightener positioned therein in which the fabric is brought into contact with the act. with an aqueous solution of a bleaching amount of an alkali metal hypochlorite and an effective amount of an alkali metal salt of silicate, wherein the yellowing of the fabric is reduced or removed. . '

DETAILED DESCRIPTION OF THE INVENTION. ·;

The present invention relates to. a method of bleaching synthetic fabrics having a brightener placed on the surface and hereinafter referred to as fabrics. · '·. '' ·. '

Fabrics can be divided into ₍ natural fabrics, i.e. fabrics made of cotton, viscose, flax, silk and wool, and others which are synthetic. They are all made of polymeric fibers of synthetic origin. The polyamide, polyester, Lvcia and Elasthane as used in the present invention are also most commonly used as synthetic fabrics. They include fabrics containing both natural and synthetic fibers.

But. these'. fabric as / ,, are not ideally white SE- during manufacture - upravuj.í optical 'fluorescent zjasňpvádlem' so that ^one gee totc / 'a brightener deposited, preferably absorbed' into »-. · - surface. of fabrics. This brightener layer. it is partially restored at least to a certain extent - at the subsequent threshold when the fabrics are washed with detergent. containing optical brighteners, which is a large proportion of all detergents. Optical fluorescent brighteners are well known in the art and can be described as compounds. which have conjugated double bonds. and / or an "aromatic structure" that allows them to absorb UV and fluoresce.

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The problems are extensively described in the prior art.

In the process of the present invention, the fabrics are contacted with an aqueous bleach solution containing two essential components other than water, i.e., an alkali metal hypochlorite and an alkali metal silicate salt.

Such a bleaching solution is commonly produced by diluting an appropriate amount of the bleaching agent in the bleaching solution. appropriate amount of water. The bleaching agent used to make the bleaching solution may be dry, i. a pulverulent or granular composition or a liquid composition. Liquid formulations are preferred over granular formulations, particularly for ease of manufacture, purity and cost reasons.

Various forms of hypochlorite, which are commercially available, or networks thereof, are used in the preparation of the liquid formulation for use in the process of the present invention. The nature of the hypochlorite cation is not critical in the present invention, and sodium hypochlorite is generally used because it is commercially available in large quantities and is economically advantageous. The bleaching solutions of the present invention contain 0.001%. % by weight to 1% by weight. active chlorine, hypochlorite, preferably &lt; 0.101 &lt; 15 &gt; 0.6 wt.%, Most preferably 0.022 wt.%. 0-5% by weight.

The second necessary. the component of the bleaching solutions used in the process of the present invention is an alkali metal salt of silicate or a mixture thereof. Again, the nature of the silicate cation is not critical, but most often it uses sodium silicate; because it is economically advantageous. ' The bleaching solutions used in the methods of the present invention. They contain a beneficial amount of silicate. By effective amount is meant an amount which is sufficient to substantially reduce the yellowing of the fabric when compared to the same silicate-free composition. In determining the amount of silicate required. _: Used, it should be noted, we found that the more silicate, the greater the effect .Therefore *

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101 • • • a and • i * «• 0 a · a. 00

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0 • 0 ·· 00 • 0 · * ♦ 0 · · ♦ • 00

And ions and all ions of silicate in the present weight, weight, weight yellowing salts. However, from a certain amount, the silicate begins to precipitate. Plus. for. given the amount of silicate the anti-yellowing effect decreases with water hardness and with increasing heavy metal content in the working solution. However, there is an anti-yellowing effect (whitening agents are used). % To 25% by weight of alkali metal silicate or mixtures thereof. - / - <

The preferred bleach solution of the present invention has a pH of 8-14, preferably 8.5-13, and more preferably 9-12. Moreover, preferred solutions of the present invention comprise. 0 ··%. % by weight, preferably / 0/005%

0.5% by weight, more preferably 0.01%

0.25 i. chelating and / or in fact; The lower pH will preferably be higher or higher. preferred: Suitable alkaline sources). % by weight, up to 5% by weight, from ,10.15% by weight, up to 0.1% by weight,

·) ... · · % by weight. to. ' % by weight. . to the filler system or mixtures thereof.

although each of these preferred shapes has no effect on the anti-yellowing effect.

Oxid oxidative, acting on the brightener so that the limits that were given are means. for pH adjustment, they strongly include hydroxide.

weight, .wt.,.

% by weight / sodium, preferably in amounts of 0 t, preferably C. 00.02, even more preferably, 0.0005 water

What. As regards chelating agents, heavy metal ions in particular prefer a free-radical action on the brightener, so that a chelating agent for said heavy metal ions is desirable.

In this embodiment, the method of the present invention is not limited to any particular filler or chelating agent, and any filler or chelating agent well known in the art may be used. effective ··· «« · «· ··· · · · ·

The chelating agents have been discussed in the jointly discussed discussion.

EP 932-3153.

. . Compositions which can be used according to the present invention further comprise, as an optional but preferred component, a buffering system that helps to maintain the pH of the bleaching solution in. even after dilution. Maintaining a suitable pH is indeed important amongst others, since it minimizes the likelihood of chlorine acid, which we have found to be responsible for damage to bleached fabrics. '_; ^f ..

In the method according to the present invention it is produced. bleachers. solution by diluting the bleaching agent in a suitable solution. amount of water . such that a concentration of hypochlorite is achieved, and. % of the total hypochlorite composition, based on active chlorine, is suitable for the bleaching compositions which contain 2 to 10% by weight of the total hypochlorite composition. %, preferably 3% by weight to 6% by weight, most preferably 4% by weight. % to 5% by weight and 0.02% by weight to 5% by weight

·. % of the total silicate composition, preferably 0.1% by weight. ý. · ·, ·>!; to 2. i by weight, most preferably i-. .'Θ, 2 '%. % by weight, and such a composition, diluted in water. 0.5 g / l. up to 10 g / l, preferably 1.0 g / l to 5 g / l. more preferably 5.0 g / l to 25 g / l. -. . . · \ .. ·. 'Bleached. the fabrics are then put into contact with the fabric ^; - bleaching solution. The time 'needed for' sufficient 'whitening from. the basis depends on the degree of contamination, but generally it is. 1 minute to 2.4 hours, preferably 3 minutes to 1 hour. 1 hour, more preferably -5 minutes to 30 minutes. Finally, the fabric is removed from the bleaching solution and the remainder of the bleaching solution is rinsed from the fabric with water. Bleaching can also be carried out w. by purifying that the bleaching chain is added to a suitable amount. detector. '

The bleaching temperature has an effect on bleaching and yellowing. More specifically, an elevated temperature accelerates bleaching, i. shortens the time needed

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99 * ♦ *......... 9 • * ·· to whiten a given impurity, but also to 'deepen' but the silicate effect against yellowing is. any temperature ...

The yellowing effect of the present invention is evaluated by comparing the composition of the present invention with the same silicate-free composition. The degree of yellowing can be; determine how visually so; instrůmenťáinim. ' yellowing between samples, by means,. the group of evaluations carried out by means of a colorimeter such as. Ganza Gri-esér * '' (eg. Datacolor® Spectraflash® White-eye · '.5.00)'. or ZET.SS ELREPHO ' ^r or available · eg ód Gard Gard Gard Gard Gard Gard Gard / Gardner®.

yellowing achieved, when evaluating. The visual difference, which caused a variety of variations. experts. Instrumentally · is .0

SF 500 -. Mačhbet other · that. are 'Ϊ

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In an embodiment of the invention. '

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The results of the reactions described below were obtained by the following test procedure. 8.5 ml of each composition was diluted into 1,000 ml water to form a bleaching medium.

The synthetic fabrics used in this test were womens' panties of the 'Rosalindá' type ¹¹ '' by Vig.uesá De. Lengeria. WITH,. Ά ·. ·. which are composed of '8Ό' (polyamide) and 20 '. Brighteners treated with lycra; The fabrics were; immersed in medium for 30 minutes. The fabrics were then removed and rinsed. Yellowing fabrics by three experts, on three repetitions in which: there is no difference between the patterns, I think there is little difference.

• ^; í '. g.seiii si. sure. is' is- big 'difference'

Positive value shows reference.

Ganz. Gríesser 'machines' ('Datacoíor -Spec t-raf las h *' SF 500).

* scale ', - 0' '

The samples were also. p ·. ·; 'Be /' evaluated by formulas: by ·.

the difference is less yellow than rated instrumentally by the pattern being

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The following compositions were tested as described.

Component Device 1. Means 2 (% by weight; AvCl-2 4, -95 5, 10 'Sodium carbonate. . -.  1 -, 25 0-, 3.-0 Sodium hydroxide' 1.40 '0' 4.5 Sodium silicate .0,5 --- Water, and minor components. the remainder to 100 and the rest up to 1ΌΌ%. Results.evaluation Ř Weaves fabric-drawn following: Ec-wall between device 1 and means 2 1. ¹ . ' Visual assessment Instrumentally. (Units of the group ..). (Ab) +4, Pers. . '. -6,9s s.— statistically significant difference..·. . ' The means 1 'is better also means. 2 _ 2 -. next ^: examples:  '' The following means ... they were also made by mixing ypš-aných. 'components' in the proportions indicated · ''

Folder. , Means 3.

(5% by weight). · ‘

AvC12 '. 4, 95

Sodium carbonate ..·. '1., - 25

Sodium hydroxide . '1,0 ..:

Sodium silicate 0, -5

-Water and minor components rest into. Í00%

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Component (A weight)

AvC12

Sodium carbonate

Sodium hydroxide. . ;

Sodium silicate

Water and minor components

The folder 'íj-.dúŤfítnoš.tní.)' '·.'

AvC12

Sodium carbonate· ·. Sodium hydroxide - Sodium silicate.-.

Water and minor components

Folder.

(ř weight)

AvC12 '· · = ^{in Λ} · - ·'

Sodium carbonate

Sodium hydroxide

Sodium silicate? '

Water and Minority Components · '

Folder ·. '

(). weight)

AvG12.

• 44 • · · ·. · · ·

4 ··· 99

Means' 4

4, 95

1,25

0,5 /.

0/5 rest dd 1O0 3

Means 5 'j'''^{of; '55}-1'

1,25. '. . ' · '' 0, 25. · O, 's-;

·. . Zbytek.Ι l rest to 100 '.?

Means 6

4,95 ',

1,2.5 .. '..' '

1.4 / ''.

1,0 - · · remainder, up to 10Q- x '

Means 1 '4.95 · 4 * 4 * 44 * 4 * 4 * 44 * .4 · 4 · 4 · 4 · • network ·· '

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Sodium carbonate ·

Sodium hydroxide

Sodium silicate

1 '2 5 <

2,0

0.25

Water and minor components, the remainder up to 100 te

1.0 · · · · · · · · · · · · · · · ·

Component Fund '8 (% by weight) , AvCÍ2. 2, o; <. ’ Sodium carbonate 1,25 Sodium hydroxide 1, .4 Sodium silicate ^{i <0} Water and minority folders the remainder to 100%.  -Component . Resource 9. ýVlhmpthosthíí 'J - 7 AvC-12 ² °. ; · ´ Uh.l i t i h s o d n-ý '1,25  1 Sodium hydroxide '· 1.4. ý Sodium tinate · .. ·· .0,5 '·' · .. Water 'and' minority 'folders rest up to 10Ό i •. . 1.  /. , Component Means 10 weight)  · AvCi2  ·. · *  2, .o ·; . . '· * Sodium carbonate 1.25. -. ·. . Sodium hydroxide 1,4- ... Sodium silicate i ·· .0,2'5. '; . Water and minority folders; rest dp 100-1  Component Means 11 (· .Weight) .Ave 12 ' ² ' °. Sodium carbonate 0, 5 Sodium hydroxide 0., . sodium silicate • '' 0,5 '. Water and Minority '· folders  the remainder to 10.0;

··

* ♦ 11 ··· Component (.¾ weight) Means 12 -AvC12 · ' Sodium carbonate'' . 7.0 0.25 Sodium hydroxide Sodium silicate Water and minority folders 0.00 0, 5  rest up to 100% Folder '. . · '. Means 13 (% / weight).,. , -CM ip. . <-. . . · Ί4 »ν · _; · · Υ · Α. AvC12 ¹ -7.0. '. ..? Sodium carbonate 25, 25 Sodium hydroxide 1 ·, 0 \ Sodium silicate · * ; i,; 5 ..i 'Λ Water and minority folder ¹ · < \ rest db- 10.0-% 'i. . Means-. 14 'Folder · ‘Ί (In weight). < ¹ '' AvC12. ^{; l} ·· /. , - / 7) -0 .. / · Sodium carbonate T  Λ. -0-, 25. ·. - 'Sodium hydroxide Sodium silicate- 1.0 · 1,0 \ Water - and - Minority folders; the rest to 100- ' • Folder '* ’* ·. Resource · 15 ('· Weight) AvC12 ' Uh l i č i t- an. s o dří ý .7,0 1, -25. Sodium hydroxide >  5.0 Sodium silicate Water and / minority folders·' 1.0 rest .to 100%

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4 *. 4 · 4 44 · 44 · '•' 4

•. 4 • 4 • 4

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· .Industrial applicability i ý ·

AND

b.

The compositions of the present invention are useful in the manufacture of compositions for bleaching synthetic fabrics onto a fabric. hypochlorite base, which ‘does not cause yellowing of these fabrics.

.industrially

Claims (7)

Ρ AT Ε NÁ NÁ CLAIMS 1. A method for bleaching a synthetic fabric having a brightener disposed therein, wherein the fabric is contacted with an aqueous solution of an alkali metal hypochlorite bleach or mixtures thereof; an effective amount of an alkali metal salt of the silicate or mixtures thereof, wherein the yellowing of said fabric is limited or totally removed. 2.. Method according to the method. ..1, .. vy z n n ... č uj · i cl -3-0.tí _; .ro that. the solution contains 15 0.0015 to 0.5% by weight 0.3. These include alkali metal salts of silicate or mixtures thereof, preferably 0.002% to 0.25% by weight. preferably 0.0025 to 0.15 wt.%. Method according to any one of the preceding claims, characterized in that the method is as follows; The solution comprises f 0,00.1. % to 1% by weight of hypochlorite. an alkali metal, preferably 0.001.5 to 0; 6% by weight, most preferably 0.0.02% by weight: up to 0.5% by weight; weight ·, 4. Process according to any one of the preceding claims, characterized in that the solution has a pH of 8 to 14, preferably 8, 5. to 13, and most preferably 9 to 12.-. A method according to any one of the preceding claims, wherein the spread further comprises: % Of alkali metal salt of carbonate, preferably 0.0000 to 0.5% by weight, most preferably 0.01-2 to 0.25% by weight. Method according to any one of the preceding claims, characterized in that the solution is produced by: diluting with a bleaching agent a composition containing 2% by weight to 2% by weight of water. 10% by weight,. preferably 3 wt.% to 6 wt.%, most preferably 4 wt.% to 5 wt.% of the alkali metal hypochlorite or a mixture thereof, and 0.02% by weight. 9 0 0 99 990 41% by weight - up to 5% by weight, preferably 0.1% by weight to 21%. by weight, most preferably Ό / -2%, by weight to 1.6% by weight, of the alkali metal salt of silicate or mixtures thereof, to a final concentration of 0.5 g / l to 100 g / l. ,. 7. A method according to any of the preceding claims, characterized in that the fabrics are contacted with the bleaching solution for 1 minute to 24 hours. preferably, the third minute to 1 hour / · .nej preferably it '.5'minut to 30 min. · ¹ 1' _8 ... _/ METHOD _t.,; According -hteréhbkO'liv ^ * - ^'> .zpředcházejícídh ./'hůřJků',·. challenge: our, cise _. The bleaching solution has a temperature of 4 ° C to 60 ° C, preferably 10 ° C to 50 ° C, most preferably 20 ° C to 60 ° C. Noc: 2 ° C. _; · '. . · '. ·' \ '·' .. .9. 1, Method. according to any one of the preceding claims, characterized in that:. More particularly, the synthetic fabrics of a polyamide and / or polyester and / or Lycra and / or E Laszhane are synthetic fabrics. ·.