AU633255B2 - Flame retardant, antistatic thermoplastic - Google Patents

Description

OPI DATE 12/12/89 AOJP DATE 25/01/90

PCF

APPLN. ID 35773 89 PCT NUMBER PCT/US89/01583 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) International Publication Number: WO 89/11501 C08K 9/00, 5/00 Al (43) International Publication Date: 30 November 1989 (30.11.89) (21) International Application Number: PCT/US89/01583 Published With international search report.

(22) International Filing Date: 14 April 1989 (14.04.89) With amended claims.

Priority data: 198,047 24 May 1988 (24.05.88) US 6 (71) Applicant: REEF INDUSTRIES, INC. [US/US]; 9209 Al- meda-Genoa, Houston, TX 77075 (US).

(72) Inventor: RAMSEY, Boyd, J. 714 Oak Harbor Drive, Houston, TX 77062 (US).

(74) Agent: BOULWARE, Margaret, One Riverway, Suite 1100, Houston, TX 77056 (US).

(81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (European patent), FR (European patent), GB (European patent), IT (European patent), LU (European patent), NL (European patent), SE (European patent).

(54)Title: FLAME RETARDANT, ANTISTATIC THERMOPLASTIC (57) Abstract A thermoplastic having both flame retardant and antistatic properties and a method for making same. The thermoplastic can be extruded into films or blown into foam. The thermoplastic can be used in a number of applications such as packaging for sensitive equipment, metal coating, temporary sheeting in nuclear and electronic industry.

FLAME RETARDANT, ANTISTATIC THERMOPLASTIC BACKGROUND AND SUMMARY OF THE INVENTION Thermoplastics have been made separately with antistatic and flame retardant properties. This invention combines both properties into one thermoplastic and the method for preparing the thermoplastic. The flame retardants and antistatic compounds are known in the art. There has been difficulty in combining the two into one thermoplastic compound.

The benefits of an antistatic and flame retardant thermoplastic are that one film, foam or other final embodiment can be used instead of a dual system. The thermoplastic of this invention can be processed into any form as long as processing temperatures are below 232 0 C. Films can be extruded, co-extruded with other thermoplastic layers and laminated with or without reinforcing layers. The product can be blown into a foam.

The thermoplastic of this invention can be used in a variety of ways. For example, sheeting can be made for temporary wall structures and floor insulation in the nuclear industry. The sheeting can also be used in the computer maintenance area to drape and floor work surfaces. In addition, the flame retardant and antistatic thermoplastic is well suited for packaging and shipping needs. The thermoplastic can be used in a sheet for wrapping and as filler to protect equipment sensitive to an electronic charge. The flame retardant bqualities are additional protection from hazards to the 'IT i i -2contents of wrapped or filled packaging. Another application is for thermoplastic coating of wires or pipe to be protected from electronic charges and fire damage. The thermoplastic can be used in many applications and it is not intended to define the uses by this description but to give useful examples of the invention.

The thermoplastic of this invention is made of conventional thermoplastic resins which are dried at 73 0 C to 121 0 C with or without a desiccant so that they contain about 0.1% or less water. The antistatic agent is a nontoxic amide which Is typically contained in a thermoplastic resin for mixing purposes. The flame retardant is similarly contained in a resin for mixing purposes and is an antimony oxide and organic halogen. The composition also contains an effective amount of hindered phenol and phosphlte stabilizer package or bisphenol polyphenol antloxidants.

The dried components are thoroughly mixed. The product may be processed in any manner compatible for thermoplastic up to temperature range of 232°C. The composition may be extruded, co-extruded with two layers of the same composition or another layer of thermoplastic, laminated with any type of film. The film laminates may be reinforced.

A blowing agent can be added to the composition and a flame retardant and antistatic foam will be produced.

DETAILED DESCRIPTION OF THE INVENTION According to a first embodiment of this invention there is provided A method for making a flame retardant and antistatic thermoplastic comprising the steps of: drying the thermoplastic resin prior to processing; drying a flame retardant compound prior to processing; drying an antistatic composition prior to processing; drying an antloxldant prior to processing; mixing thoroughly the thermoplastic resin, flame retardant compound, antioxidant and antistatic composition prior to processing wherein each of components to is dried to a water content of 0.1% or less; and processing the mixture to make a thermoplastic product at temperatures below 232 0

C.

According to a second embodiment of this invention there Is 568u I

I

4 i 2A provided a flame retardant and antistatic thermoplastic comprising: a thermoplastic resin with 0.1% or less water content by weight; an antistatic compound of thermoplastic resin containing nontoxic amide with 0.1% or less water a flame retardant compound of antimony oxides and 6% organic halogen weight between 27% and 95% by weight o a hindered phenol and phosphite content at least 0.2% by weight of the a hindered phenol and phosphite content at least 0.2% by weight of the According to a third embodiment content by weight; thermoplastic resin containing 2% with 0.1% or less water content by f the thermoplastic product; antioxidant with 0.1% or less water thermoplastic product and antioxidant with 0.1% or less water thermoplastic product.

of this invention there is provided a flame retardant and antistatic thermoplastic comprising: a thermoplastic resin with 0.1% or less water content by weight; an antistatic compound of thermoplastic resin containing nontoxic amide with O.l1% or less water content by weight; a flame retardant compound of thermoplastic resin containing 2% antimony oxides and 6% organic halogen with 0.1% or less water content by weight between 27% and 95% by weight of the thermoplastic product; a hindered phenol and phosphite antioxidant with 0.1% or less water content at least 0.2% by weight of the thermoplastic product.

According to a fourth embodiment of this invention there is provided a reinforced flame retardant and antistatic laminate film comprising: two layers of an extruded film of thermoplastic with 0.1% or less water content by weight; said film containing an antistatic compound of a nontoxic amide with 0.1% or less water content by weight; said film containing a flame retardant compound of thermoplastic resin containing 2% antimony oxides and 6% organic halogen with 0.1% or less water content by weight between 27% and 95% by weight of the thermoplastic product; said film containing at least 0.2% of an antioxidant of a hindered phenol and phosphite with 0.1% or less water content by weight; a nonwoven reinforcing filament laid out in a diamond grid between said layers of film; and said nonwoven reinforcing filament grid held between said film layers by an adhesive layer with a flame retardant of antimony oxides and organic halogen.

'H/1568u 2B did nunwoven einfurcing filament grid iJ I be 1 nJ i layers by an adhesive la-- v te ardant of antimony oxides and The thermoplastic chosen for this invention can be any type including but not limited to polyethylene of any density or form such as high density or linear low density polyethylene, poly- propylene of copolymers or homopolymers, ethylene vinyl acetate, ethylene methylacrylic acid and mixtures thereof. The thermoplastic is chosen considering factors such as cost, strength, 568u stiffness and final product configuration in the particular application.

All the ingredients including the thermoplastic resin are dried prior to mixing to reduce the water content to 0.1% or less by weight. The drying can take place in an oven with or without a desiccant such as granular calcium sulfate. The components are typically dried at 73 0 C for three hours. The drying range can go up to 121°C. The temperature and length of drying time 0o is dependent on the achievement of the 0.1% water content.

The other ingredients are effective amounts of flame retardant, antistatic agent and antioxidant.

These additives are commercially available in resins.

1 The resin containing the additive promotes uniform mixing with the thermoplastic. The flame retardant, antistatic agent and antioxidant are dried as described above for the thermoplastic. All the ingredients contain 0.1% or less water prior to mixing.

O The antistatic compound is a'nontoxic amide. The commercially available additive is 5% nontoxic amide in a low density polyethylene manufactured as Statcease CD by Techmer Corporation. The Statcease product with active ingredient can be used in a 5% to 65% range in LA the composition of this invention.

The flame retardant is antimony oxide specifically antimony trioxide or antimony pentoxide and an organic halogen. A commercial product by Ampacet Corporation (Product Number 11371) includes effective amounts of i? antimony trioxide and decabromo- diphenyloxide in a linear low density polyethylene master batch. The antimony trioxide is 2% by weight and the organic halogen is 6% by weight in the4=A&fe product. The fire retardant product is used in a range of 27% to 95% by V- r C>9r\o c weight of thejfinal product.

The final product contains at least 0.2% of an antioxidant hindered phenol and phosphite stabilizer -j is r SUBSTITUTE

SHEET

-3i L1 1

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package. A commercially available product is Ciba-Geigy Irganox 1010 which is added to the mixture.

The starting materials can be mixed in any order of addition with the complete and thorough mixing after all the materials are added. The processing steps should not exceed 232 0

C.

The thermoplastics of this invention are self extinguishing once the source of heat is removed and passes the UL V-2 test. The flame retardant properties were tested by the National Fire Protection Association procedure and passed the large-scale and small-scale test. The material also has static decay properties in compliance with U.S. Military Specification 81705B. The thermoplastic can be extruded to form a film. The product can be used as one layer of a multi-layer laminated film with the film of this invention making up at least one of the layers. Any type of adhesive can be used such as a pressure sensitive adhesive, acrylic, polyvinyl chloride, acrylonitrile, silicone, solvent, hot melt or rubber based. A flame retardant package of antimony trioxide and organic halogen is added to the adhesive such that the final content includes about 1.1% 3 and about 5.6% organic halogen.

EXAMPLE 1 A film was made of the following ingredients dried for 3 hours at 73 0 C: 48% low density polyethylene; 2% Irganox 1010; 35% Ampacet Product Number 11371; Techmer Statcease. The materials were thoroughly mixed and extruded to form a film.

EXAMPLE 2 Two films as described in Example 1 were used to make a 2-ply reinforced laminate. The adhesive was a solvent based acrylic with Sb 2 0 3 organic halogen flame suBSTT retardant additive. The adhesive is coated at 1 mil dry thickness. The adhesive Layer holds into place a nonwoven reinforcing filament grid. A typical adhesive formula is shown in Table 1 which includes the volatile starting materials. After the adhesive dries, higher percentages of the flame retardant compounds are present. On one film coated with adhesive a nylon multifilament 460 denier with a Z twist is laid out in a diamond pattern grid. The grid is formed by filaments in two substantially parallel sets laid at 450 angles.

The strands are laid out and spaced about 0.5 inches apart. The two thicknesses of film with the adhesive and reinforcing grid in between are passed between pressure rollers to form the laminate.

TABLE 1 Fire Retardant Adhesive Formula Hexane 16.72% Ethyl Acetate 26.05% Antimony Oxide 0.65% Organic Bromine 3.24% Acrylic Concentrate 53.34% EXAMPLE 3 The film as described in Example 1 or the reinforced laminate as in Example 2 may be coated with a pressure sensitive adhesive to form a pressure sensitive tape. The adhesive may be a solvent based acrylic deposited at 66.66 kgs per ream application weight. The adhesive may be applied by direct gravure or roll transfer coating. A release paper is provided.

C1* ill 111~1~1 EXAMPLE 4 The film as described in Example 1 or the reinforced laminate as in Example 2 may be coated with a hot melt adhesive to form a pressure sensitive tape. The adhesive is a rubber based hot melt adhesive commonly available from National Starch and Chemical Co. or Findley Adhesives, Inc. The adhesive is applied at a thickness of 6 mils to produce a permanent bonding tape.

A release paper is provided.

EXAMPLE The thermoplastic as described may be mixed with a typical blowing agent of a chlorofluorocarbon such as Genetron 12 manufactured by Allied Signal Corp. and extruded into a foamed sheet. The blowing agent is injected into a molten phase of the thermoplastic material. The mixture is then forced through a die and upon the drop of pressure from inside the extruder to atmospheric pressures. The blowing agent expands to form a foamed sheet of density 13.3 to 17.8 kgs per cubic foot.

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Claims (23)

1. A method for making a flame retardant and antistatic thermoplastic comprising the steps of: drying a thermoplastic resin prior to processing; drying a flame retardant compound prior to processing; drying an antistatic composition prior to processing; drying an antloxidant prior to processing; mixing thoroughly the thermoplastic resin, flame retardant compound, antioxidant and antistatic composition prior to processing wherein each of components to is dried to a water content of 0.1% or less; and processing the mixture to make a thermoplastic product at temperatures below 232 0 C.

2. The method of claim 1 wherein steps and the drying process is carried out until 0.1% water or less by weight remaining in the resin, flame retardant compound, antloxidant and antistatic compositions and the drying temperature is between 73 0 C and 121 0 C.

3. The method of claim 1 or claim 2 wherein steps (c) and the drying process of the resin, flame retardant compound, antioxidant and antistatic compositions is performed in the presence of a desiccant.

4. The method of any one of claims 1 to 3 wherein step the mixture is extruded at process temperatures below 232 0 C.

5. The method of any one of claims 1 to 4 wherein during step (e) a blowing agent is added during step and the material is processed into a foam product.

6. The method of any one of claims 1 to 5 wherein the antistatic agent is a nontoxic amide.

7. The method of any one of claims 1 to 6 wherein the thermoplastic product comprises between 27% and 95% by weight of the flame retardant compound which comprises a thermoplastic resin comprising 2% antimony oxides and 6% organic halogen with 0.1% or less water content by weight.

8. A flame retardant and antistatic thermoplastic comprising: a thermoplastic resin with 0.1% or less water content by weight; KEH/1568u i i i 111~~ -8- an antistatic compound of thermoplastic resin containing nontoxic amlde with 0.1% or less water content by weight; a flame retardant compound of thermoplastic resin containing 2% antimony oxides and 6% organic halogen with 0.1% or less water content by weight between 27% and 95% by weight of the thermoplastic product; a hindered phenol and phosphite antioxidant with 0.1% or less water content at least 0.2% by weight of the thermoplastic product.

9. The flame retardant and antistatic thermoplastic of claim 8 wherein said flame retardant compound is a thermoplastic re:in containing 2% antimony oxides and 6% organic halogen.

The flame retardant and -antistatic thermoplastic of claim 8 or claim 9 wherein the thermoplastic product is an extruded thermoplastic film.

11. The flame retardant and antistatic thermoplastic sheet of any one of claims 8 to 10 wherein the thermoplastic product is a co-extruded film of at least two film layers, at least one of said films having the composition of any one of claims 8 to

12. A flame retardant and antistatic thermoplastic sheet wherein the thermoplastic product is at least two layers of laminated film at least one of said films having the composition of any one of claims 8 to 11 and the laminate adhesive includes a flame retardant.

13. The flame retardant and antistati thermoplastic sheet of any one of claims 8 to 11 wherein the thermoplastic product is at least two layers of laminated film at least one of said films having the composition of any one of claims 8 to 11; laminate adhesive layer includes a flame retardant; and a nonwoven reinforcing, filament laid out In a diamond grid is held between two layers of film by the adhesive layer.

14. The flame retardant and antistatic thermoplastic of claim 8 or claim 9 which is blown to make a foam.

A flame retardant and antistatic thermoplastic film comprising: an antistatic compound of thermoplastic resin containing nontoxic amlde with 0.1% or less water content in 5% to 65% by weight of the thermoplastic product; a flame retardar.t compound of a thermoplastic resin containing 2% antimony oxides and 6% organic halogen with 0.1% or less water content in 27% to 95% by weight of the thermoplastic product; KEH/1568u I -9- a hindered phenol and phosphite antioxdant with 0.1% or less water content in at least 0.2% by weight of the thermoplastic product; and a thermoplastic with 0.1% or less water content making up the balance of the product selected from the group consisting essentially of polyethylene, polypropylene, ethylene vinyl acetate, ethylene methylacrylic acid and mixtures thereof.

16. A reinforced flame retardant and antistatic laminate film j comprising: two layers of an extruded film of thermoplastic with 0.1% or less water content; said film containing an antistatic compound of a nontoxic amide with 0.1% or less water content by weight; said film containing a flame retardant compound of thermoplastic resin containing 2% antimony oxides and 6% organic halogen with 0.1% or less water content by weight between 27% and 95% by weight of the thermoplastic product; said film containing at least 0.2% of an antioxidant of a hindered phenol and phosphite with 0.1% or less water content by weight; a nonwoven reinforcing filament laid out in a diamond grid between said layers of film; and said nonwoven reinforcing filament grid held between said film layers by an adhesive layer with a flame retardant of antimony oxides and organic halogen.

17. A reinforced flame retardant and antistatic laminate film of claim 16 wherein said nonwoven reinforcing filament is nylon multifilament.

18. A flame retardant and antistatlc thermoplastic made by the process of any one of claims 1 to 7.

19. A flame retardant and antistatic thermoplastic made by the process of any one of claims 1 to 7 wherein the thermoplastic Is an olefin.

A method of making a flame retardant and thermoplastic resin substantially as hereinbefore described with reference to any one of the Examples.

21. A flame retardant and antistatic thermoplastic substantially as hereinbefore described with reference to any one of the Examples. KEH/1568u

22. A substantially Examples.

23. A substantially Examples. 10 flame retardant and antistatic thermoplastic film as hereinbefore described with reference to any one of the reinforced flame retardant and antistatic laminate film as hereinbefore described with reference to any one of the DATED this SEVENTEENTH day of NOVEMBER 1992 Reef Industries, Inc. Patent Attorneys for the Applicant SPRUSON FERGUSON KEH/1568u I I ~T~X INTERNATIONAL SEARCH REPORT Iittenalonal Applicaton No PCT/US 89/01583 1. CLASSIFICATION OF SU10JECT MATTER (it several classification symbols apply, Indicate all)I According to Interntional Patent CIass1119ato MIP of to both National Clesaiflcatien and IPC IPC 4 C 08 K 9/00, C 08 K 5/00 II. FIELDS SEARCHED Minimum" Documentation SearchedI Classification System IClassification Symbols IPC 4C08 K Documentation Seached other tihan Minimnum, Documentation to the Extent that such Documents are Included In the Fields Searched 0 Ill. DocuMENITS CONSIDERED TO S1 RELEVANT' Category 1 Citation of Document."1 with Indication, whale appropiate, ot the relevant passages Is laevant to Claim No." Y EP, A, 0144015 (MONTEPOLINERI) 12 June I1-15 1985, see claim 1; page 6, lines 19-25 Y FR, A, 2346398 (NATIONAL DISTILLERS AND 1-15 CHEMICAL CORP.) 28 October 1977, see claim 1; page 3, lines 12-36 K DE, A, 2432677 (RUHRKOHLE) 20 November 3 1975, see page 1, line 22 page 2, line 7; claim 1 *Special catgofis af cited docu-ents: If IT" late docuwm Published alter the Interntiontal filing date "A dcumnt efiingthegenralstae s tie at wichIs tet or priority, date and not In conflict with the application but "A*docmen deinitite sme 01 he wichIs ot cited to undeestand the principle of thee" underlying the considered to be o ptiua rlvNBCeivnto earlier document bW published en of 61140 the 104014i601111 X" decument' e0 taiculer I-evnce:, the "lsmed inventlen filing date cannot be considered neve or cannot be ceneloere to document whicht may thries doubts en priorit clms orinvolve an inventive ste which Is cited to establish the publication dateo0 of he I document of poutcul:or v reeac;*the claimd howentaon citation or other speiml resetn WU speciflid) cannot beconsiered to involve an inventive ato" when the document refonms ts an o"a dioeteure. use. inhibltin Wi documen Is combined with oe or more other such docu- other meanis momflta such cembinetlet being obvious to a person, shille IP document published prio to the k9fintreteo filingl dat bWA It the 611. later than the prianity date clainmed "a ecmemo member of the sam patent lamlly IV. CERTIFICATION Date of the Actual Completion of the Wntedtlne Seach 1st August 1989 International Searching Authoity EUROPEAN PATEMI OFFICE Form PCTIISA MIS0 'sen sheet) yjwp Ion) Oats 04 MailIng 54 tltl~ Irttsrnotieeal Searnls R~ort U ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL PATENT APPLICATION NO. US 8901583 SA 28607 This annex lists the patent family members Meating to the patent documents cited in the above-mentioned international search report. The membrs are as contained in the European Patent Office EDP Fie on 21/08!49 The European Patent Office is in no way liable for these particulars which are mierely given for the purpose of information. Patent documient Publication Patent famnily Publication cited in search report date memberls) date EP-A- 0144015 12-06-85 CA-A- 1240100 02-08-88 DE-A- 3474031 20-10-88 JP-A- 60118726 26-06-85 US-A- 4666947 19-05-87 FR-A- 2346398 28-10-77 BE-A- 852991 29-09-77 DE-A- 2713859 13-10-77 JP-A- 52135347 12-11-77 LU-A- 77031 22-07-77 NL-A- 7703391 03-10-77 SE-A- 7703565 30-09-77 DE-A- 2432677 22-01-76 None M For mote details about this annex see official Journal of the European Patent Office, No. 12/82