AU2004226975B2

AU2004226975B2 - Flame-retardant plastic composition, yarn and textile structure coated therewith

Info

Publication number: AU2004226975B2
Application number: AU2004226975A
Authority: AU
Inventors: Isabelle Conesa; Francois-Xavier Damour
Original assignee: Chavanoz Industrie SARL
Current assignee: Chavanoz Industrie SARL
Priority date: 1999-03-23
Filing date: 2004-11-04
Publication date: 2007-12-20
Anticipated expiration: 2020-03-23
Also published as: AU2004226975A1

Description

1 P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention title: Flame-retardant plastic composition, yam and textile structure coated therewith The invention is described in the following statement: 7617833 1.doc r 1 1 SFlame-retardant plastic composition, yarn and textile structure coated therewith (Ni Field of the Invention z The present invention relates to a halogen-free flame-retardant composition intended for coating a substrate, for example, yarns or textile structures for the manufacture of sun screens such as blinds or curtains. More specifically, the invention relates to a halogen-free flameretardant composition, in the plastisol state, comprising at least one acrylic resin and an NO intumescent agent dispersed in a plasticizer.

Background to the Invention (Ni In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date part of common general knowledge; or known to be relevant to an attempt to solve any problem with which this specification is concerned.

Specialty fabrics obtained from yarns when used in certain environments are subject to fire behavior requirements defined by national or international regulations and/or procedures. For example, furnishings such as blinds for both the interior and exterior of buildings are subject to regulation.

For example, the regulations applicable to such fabrics in the Federal Republic of Germany define various requirements classified by the length of the specimen destroyed by the fire and by the temperature of the combustion smoke, these classifications being identified by the letters B1 to B3, the letter B1 characterizing the best fire behavior achievable by a material comprising organic materials.

The regulations applicable in France also define various requirements, such as smoke emission which is identified by the letters FO to F5, F3 being the best behavior achievable by a material containing a halogenated polymer. The regulations also classify the ignition time of the fabric which is identified by the letters MO to M4, the letter M1 identifying the best fire behavior generally achievable by a material comprising organic materials.

For the purposes of meeting the requirements in terms of fire behavior, it is known to Sincorporate into any plastic composition a suitable intumescent agent, formulated with the o resin so as to achieve the required level of flame retardation.

z It is generally known that there are composite yams, which the Applicant manufactures and sells, comprising: ra core comprising a continuous yarn, especially made of an inorganic material, for Sexample glass; a sheath or jacket comprising a matrix consisting of at least one chloropolymer Smaterial, for example a polyvinyl chloride (PVC); a flame-retardant mineral filler incorporated into and distributed in said matrix; and a plasticizer.

Typically, such a yarn is obtained by coating the core with a plastisol comprising the chloropolymer material, for example PVC, and the plasticizer, and then by gelling the plastisol around the core.

The Applicant has disclosed a halogen-free flame-retardant plastic composition, described in document FR-A-2 755 973, applicable to a substrate, such as a yam made of a mineral or organic material, of natural or synthetic origin, such as glass, polyester, polyamide, polypropylene, polyethylene, and containing no halogen or halogenated compound. This flame-retardant plastic composition includes a binding fraction, which binds said composition, and an intumescent agent consisting at least of a strong-acid compound, which is thermally degradable, and a polyhydric carbon compound. Said binding fraction as such has a limiting oxygen index (LOI) at least equal to 25% and the intumescent agent essentially consists of said strong-acid compound and said polyhydric carbon compound, the solids content of the composition having a weight ratio of said strong-acid compound to said polyhydric carbon compound of between 1.5 and 2, and preferably of 1.85.

The flamed-retardant composition described in document FR-A-2 755 973 may be in solid, molten or liquid form. Preferably, this composition is in the form of an aqueous dispersion.

Even with the development of this flame-retardant plastic composition, there has still been a need for improvement because the method of coating a substrate with such a composition can o lead to a detrimental effect on the properties of the yarn or of the composite structure obtained, Z in terms of heat-sealability and resistance to both high and low temperatures. As a result, the Applicant has been investigating an improved coating composition.

t Summary of the Invention O It has now been found that it is possible to avoid using high temperatures to melt the resin during the coating process leading to less degradation of the final properties of the product and less degradation of the intumescent agent.

This is achieved by using a flame-retardant plastic composition in the ungelled plastisol state, that is to say with a both the acrylic resin and the intumescent agent distributed in a plasticizer, which enables the use of a coating method in which the core is passed through a die, with peripheral delivery around the core of a sheath of the flame-retardant plastic composition.

According to the invention, there is provided a halogen-free fire-retardant plastic composition suitable for coating a substrate, wherein the halogen-free fire-retardant plastic composition comprises at least one acrylic resin and at least one intumescent agent dispersed in a plasticizer; and wherein the halogen-free fire-retardant plastic composition has the following properties: a) it is in the plastisol state; b) it exhibits, at low shear rates, Newtonian-type behavior at a viscosity of less than or equal to about 6000 mPa.s; and c) it exhibits, at high shear rates, pseudoplastic-type behavior.

The coating process uses dies with a high shear rate (for example of the order of at least 000 to 20 000 s 1 or even 100 000 therefore the rheological properties of the flameretardant compositions are important. At low shear rates (for example less than 300 400 s1), the plastisol exhibits Newtonian-type behavior with a viscosity of less than or equal to 6000 mPa.s (measured using a Brookfield RVT viscometer at 20 revolutions per minute) and, at r high shear rates (for example greater than 10 000 the plastisol exhibits pseudoplastic-type C1 behavior.

0 As a person skilled in rheology will know that 'Newtonian behavior' is characterized by a shear stress which varies linearly with shear rate, and 'pseudoplastic behavior' is characterized by a shear stress which reaches a limiting value when the shear rate increases.

In the case of the present invention, Newtonian behavior is revealed when it is possible to O measure the viscosity of the flame-retardant composition using any suitable method, whether I standardized or not, and pseudoplastic behavior is revealed by the ability of the flameretardant composition to pass, without flow, through a coating die with a high shear rate, for 10 example of the order of 15 000 to 20 000 s l Preferably, so as to preserve the properties of the composite yarn obtained, especially its heatsealability and its weatherability, the weight proportion of the plasticizer comprising a phosphate is at most equal to 200% with respect to the weight of acrylic resin and/or the weight proportion of the intumescent agent is at most equal to 200% with respect to the weight of acrylic resin.

The plasticizer comprises predominantly, by weight, an organic phosphate, preferably with a phthalate.

The proportion by weight of intumescent agent is between 50 and 200%, preferably between 150 and 200%, by weight of resin.

Any composite yarn or any composite textile structure, capable of being obtained by coating and then gelling a flame-retardant composition as defined above may achieve a fire resistance according to French Standard NFP 92503, especially classification level M1, and also good weatherability, meeting the ISO 105 standard, and finally good heat-sealability.

In the description and claims, the terms and expressions indicated below have the following meanings: an "acrylic resin" is any synthetic polymer derived from propenoic acid; r S"a thermally degradable strong-acid compound" is a compound which releases a strong Cl acid either by itself or in situ from a precursor, at high temperature, that is to say at between o about 100 0 C and about 250 0

C;

S- "a polyhydric carbon compound" is a compound generally chosen from the various classes of carbohydrates and having a relatively high amount of carbon and many hydroxyl tI sites; s0 "a liquid phosphorus derivative" is a flame-retarding product which comprises

(N

CN phosphate groups and is in liquid form; O "a gas-generating agent" is a product which, by thermal degradation due to the effect of temperature, releases a gas, for example carbon dioxide or ammonia; "a plastisol state" is a dispersion of acrylic resin, intumescent agent polymers, fillers and various additives in a plasticizer.

In another preferred embodiment according to the invention, the flame-retardant plastic composition further comprises a phosphate-type plasticizer. With a phosphate/phthalate-type plasticizer, the performance is better, in terms of low viscosity, and there is less plasticizer exudation after gelling.

As examples of phthalate-type plasticizers, mention may be made of the plasticizers PALATINOL C and PALATINOL N available from BASF.

As phosphate-type plasticizers, mention may be made of DISFLAMOLL DPO and DPK® available from Bayer.

As examples of phosphate/phthalate-type plasticizers, mention may be made of those available from Solutia.

In yet another preferred embodiment according to the invention, the acrylic resin is a homopolymer or copolymer based on methyl methacrylate.

Such a resin may, for example, be chosen from the resins BM 310® and BM 410® available from Rohm.

O The flame-retardant plastic composition according to the invention may also include UV C stabilizers and/or opacifiers and/or pigments and/or viscosity-reducing processing aids.

0 0 As UV stabilizers, mention may especially be made of compounds of the benzophenone type, Ssuch as TINUVIN P available from Witco, or compounds of the benzotriazole type, such as TINUVIN 320 available from Witco or LOWILITE 55 available from Great Lakes.

As opacifiers, mention may especially be made of calcium carbonates and zinc sulfides.

N\

C1 As pigments, mention may especially be made of products from the IRGALITHE or SCHROMOPHTAL ranges available from Ciba-Geigy.

As viscosity-reducing processing aids, mention may especially be made of the viscosity reducers available from Byk Chemie.

The intumescent agent of the composition according to the invention comprises at least one strong-acid compound.

Preferably, the thermally degradable strong-acid compound is chosen from the group consisting of phosphoric acids, boric acids, and salts of these acids with a volatile cation, and preferably ammonium polyphosphate. This is because the acid source agent is chosen to be able to dehydrate, effectively, the carbon source agent, if it is present, above a certain temperature or in the presence of a flame, and to release the acid in temperature ranges close to the ignition temperature of the substrate to be flame-retardant.

The intumescent agent may also comprise a polyhydric carbon compound. The polyhydric carbon compound is preferably a starch or a polyhydric alcohol, and more preferably pentaerythritol. This is because these agents contain a relatively high amount of carbon and have many hydroxyl sites, thereby favoring the formation of a highly expanded residue.

The intumescent agent may also comprise liquid phosphorus derivatives which make it possible to further reduce the viscosity of the fluid plastisol. These derivatives are preferably chosen from products of the FYROL® range available from Akzo.

The intumescent agent may also comprise gas-generating agents such as, in particular, melamine.

r -7- In a highly preferred embodiment according to the invention, the flame-retardant plastic r composition comprises, by weight: 0 Z acrylic resin 100.00 parts phosphate/phthalate plasticizers 125.00 parts In liquid phosphorus derivatives 5.00 parts O ammonium polyphosphate and melamine 97.50 parts 50/50 pentaerythritol/melamine 52.00 parts Another subject of the invention is a flame-retardant composite yarn comprising a core of low combustibility, made of a mineral or organic material, for example a halogen-free material, and a sheath made of a plastic capable of being obtained from the flame-retardant composition as defined above. The material of the core is, for example, a continuous glass filament.

The core made of halogen-free material of the composite yarn according to the invention may be chosen from the group consisting of a yarn made of a mineral or organic material, of natural or synthetic origin, such as glass, glass filament, polyester, polyamide, polypropylene and polyethylene. Preferably, a core made of a glass yarn or a continuous glass fiber, or filament, will be chosen.

The subject of the invention is also a textile structure in which the composite yarns as obtained above are assembled or entangled.

Another subject of the invention is a substrate of low combustibility, for example a textile structure, coated with a resin layer, obtained by coating and then gelling a flame-retardant composition as defined above.

Further subjects according to the invention are, respectively, a sun screen, a sign, and a covering for walls or ceilings, comprising a textile structure as defined above.

I

Examples The examples which follow illustrate the invention but do not in any way limit the scope of the appended claims.

EXAMPLE 1: Formulation I of a fire-retardant plastic composition Plastisol: Acrylic resin (BM 310 from Rohm) Phosphate/phthalate plasticizer 100.00 parts 125.00 parts Intumescent agent: Ammonium polyphosphate Pentaerythritol 120.00 parts 31.00 parts 31.00 parts Melamine Lubricant: Silicone oil 2.50 parts Such a fire-retardant plastic composition has, in its Newtonian range, a viscosity of 4600 mPa.s measured using a Brookfield RVT viscometer at 20 revolutions per minute. Moreover, at high shear rates, it is pseudoplastic.

The fire behavior tests were carried out on glass fabrics coated with the fire-retardant plastic composition described above, as well as on composite yams formed from about 54% (or of continuous glass filament and from 46% (or 50%) of the fire-retardant plastic composition described above.

The results of the tests carried out demonstrate that the Ml classification of the NFP 92503 Standard can be assigned to the textiles thus obtained.

r -9- EXAMPLE 2: Formulation II of a flame-retardant plastic composition Plastisol: Acrylic resin (BM 310) from Rohm Phosphate/phthalate plasticizer 100.00 parts 125.00 parts Intumescent agent: Ammonium polyphosphate Pentaerythritol BUDIT 3077B fire-retardant system (available from Budenheim) 38.00 parts 31.00 parts 150.00 parts Lubricant: Silicone oil 2.50 parts Such a fire-retardant plastic composition has, in its Newtonian range, a viscosity of 6000 mPa.s measured using a Brookfield RVT viscometer at 20 revolutions per minute. Moreover, at high shear rates, it is pseudoplastic.

The same tests as those described in Example 1 were repeated, giving the same results.

EXAMPLE 3: Formulation III of a flame-retardant nlastic comnosition Plastisol: Acrylic resin (BM 310) from R6hm Acrylic resin (VP 8744) from R6hm Phosphate/phthalate plasticizer 80.00 parts 20.00 parts 130.00 parts r Intumescent system: Ammonium polyphosphate Pentaerythritol Melamine Liquid phosphorus derivative 115.00 parts 31.00 parts 31.00 parts 5.00 parts Lubricant: Silicone oil 2.50 parts Wetting agent 5.00 parts Such a fire-retardant plastic composition has, in its Newtonian range, a viscosity of 4300 mPa.s measured using a Brookfield RVT viscometer at 20 revolutions per minute. Moreover, at high shear rates, it is pseudoplastic.

EXAMPLE 4: Formulation IV of a fire-retardant plastic composition Plastisol: Acrylic resin (BM 310) from Rohm Acrylic resin (VP 8744) from Rohm Phosphate plasticizer Intumescent system: Ammonium polyphosphate Pentaerythritol Melamine 80.00 parts 20.00 parts 130.00 parts 115.00 parts 31.00 parts 31.00 parts

I

-11- Lubricant: Silicone oil 2.50 parts 0 Such a fire-retardant plastic composition has, in its Newtonian range, a viscosity of 5250 SmPa.s measured using a Brookfield RVT viscometer at 20 revolutions per minute. Moreover, at high shear rates, it is pseudoplastic.

Many other fire-retardant plastic compositions may be formulated and qualified by routine Stests, based on the above examples, and on the following supplementary considerations: the final rheological behavior depends largely on the plasticizer used, more specifically on its chemical nature and its proportion; in this regard, a plasticizer comprising a phthalate must be preferred; the proportion of the components or compounds in the intumescent agent has little effect on the final rheological behavior, since in particular the actual intumescent properties are desirable; in contrast, the proportion of the intumescent agent is important with regard to the final rheological behavior. This proportion must be limited, otherwise it will impair the fire retardancy; any viscosity-reducing additive allows these rheological properties to be adjusted, if necessary.

The word 'comprising' and forms of the word 'comprising' as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions.

Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

Claims

2. The plastic composition as claimed in claim 1, characterized in that the weight proportion of the plasticizer comprising a phthalate is at most equal to 200% with respect to the weight of acrylic resin.
3. The plastic composition as claimed in claim 1, characterized in that the weight proportion of the intumescent agent is at most equal to 200% with respect to the weight of acrylic resin.
4. The plastic composition as claimed in claim 1, characterized in that the weight proportion of the plasticizer comprising a phthalate is at most equal to 200% with respect to the weight of acrylic resin and the weight proportion of the intumescent agent is at most equal to 200% with respect to the weight of acrylic resin. The plastic composition as claimed in claim 1, characterized in that the plasticizer comprises predominantly, by weight, an organic phosphate.
6. The plastic composition as claimed in claim 5, characterized in that the plasticizer further comprises a phthalate. 13
7. The plastic composition as claimed in claim 2, characterized in that the proportion by weight of the plasticizer is between 100 and 200% by weight of 0 resin. z
8. The plastic composition as claimed in claim 7 characterized in that the proportion by weight of the plasticizer is between 120 and 145%, by weight of Sresin. NO 9. The plastic composition as claimed in claim 3, characterized in that the proportion by weight of the intumescent agent is between 50 and 200% by weight of resin. The plastic composition as claimed in claim 9, characterized in that the proportion by weight of the intumescent agent is between 150 and 200% by weight of resin. I. A flame-retardant composite yarn comprising a core made of a material of low combustibility and a sheath made of a plastic capable of being obtained from the halogen-free fire-retardant plastic composition as claimed in any one of claims 1 to 10, characterized in that the yam is obtained by coating said core with the halogen-free fire-retardant plastic composition.
12. The yarn as claimed in claim 11, characterized in that the material of the core is a halogen-free material.
13. The yarn as claimed in claim 11, characterized in that the material of the core is a continuous glass filament.
14. A textile structure comprising a substrate of low combustibility and at least one layer of a plastic capable of being obtained from the halogen-free fire- retardant plastic composition as claimed in any one of claims 1 to characterized in that the structure is obtained by coating the substrate the halogen-free fire-retardant plastic composition. The textile structure as claimed in claim 14 characterized in that the substrate is a halogen-free substrate. r -14-
16. A textile structure in which yars as claimed in claim 11 are assembled or O Oentangled. 0 17. A sun screen comprising a textile structure as claimed in any one of claims 14 to 16.
18. A sign comprising a textile structure as claimed in any one of claims 14 to 16. 1 19. A covering for walls or ceilings, comprising a textile structure as claimed in Sany one of claims 14 to 16. CHAVANOZ INDUSTRIE 4 NOVEMBER 2004 0",