WO1995028439A1 - Moulding compositions containing a polyamide - Google Patents

Moulding compositions containing a polyamide Download PDF

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Publication number
WO1995028439A1
WO1995028439A1 PCT/GB1995/000875 GB9500875W WO9528439A1 WO 1995028439 A1 WO1995028439 A1 WO 1995028439A1 GB 9500875 W GB9500875 W GB 9500875W WO 9528439 A1 WO9528439 A1 WO 9528439A1
Authority
WO
WIPO (PCT)
Prior art keywords
composition
moulding
polyamide
nylon
composition according
Prior art date
Application number
PCT/GB1995/000875
Other languages
French (fr)
Inventor
Richard Scott Barnes
Richard Stuart Williams
Original Assignee
T & N Technology Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by T & N Technology Limited filed Critical T & N Technology Limited
Publication of WO1995028439A1 publication Critical patent/WO1995028439A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3412—Heterocyclic compounds having nitrogen in the ring having one nitrogen atom in the ring
    • C08K5/3415—Five-membered rings

Definitions

  • This invention is concerned with moulding compositions which contain a polyamide, e.g. nylon 6 or nylon 66, and is especially concerned with such compositions which contain a filler, eg magnesium hydroxide as a flame retardant.
  • a polyamide e.g. nylon 6 or nylon 66
  • a filler e.g magnesium hydroxide as a flame retardant.
  • Polyamides such as nylons, are widely used for moulding components and, for some moulding applications, are mixed with a flame-retardant so that the moulded component exhibits flame retardant characteristics.
  • Such applications include electrical lamp-holders, and switch housings.
  • Magnesium hydroxide is a flame retardant which has been suggested for use with nylon. This material, when subjected to a flame, decomposes endother ically with the liberation of water. Nylon containing magnesium hydroxide has, however, been found to be difficult to mould because of its high melt viscosity and, furthermore, it is found that the mouldings have obvious surface defects which render them unacceptable commercially. Such surface defects manifest themselves by the appearance of white patches on the surface of the moulding. Various attempts have been made to overcome this problem but without achieving complete success. The most successful previous attempt known to the applicants involves the addition of organic sulphonamide to the moulding composition (see GB 2,237,573A) but even this has not achieved total success.
  • the invention provides a moulding composition containing a polyamide characterised in that the composition also contains phthalimide.
  • Phthalimide is recorded in the Chemical Abstract Service Registry under number CAS 85-41-6.
  • a moulding composition according to the invention is found to produce mouldings with reduced surface defects.
  • the composition is also found to be easier to mould making it possible to mould compositions with higher concentrations of fillers.
  • the phthaimide provides 0.1 to 5 per cent by weight of the composition, eg 0.5 to 5 per cent.
  • about 1 per cent of phthalimide is found to result in saleable mouldings, ie with an acceptable level of surface detects, and 2.5 per cent was found to result in substantially no discernable surface defects.
  • the polyamide may be nylon 6, nylon 66, nylon 6.12, nylon 6.10 or another suitable polyamide.
  • the polyamide may also be a co-polymer of two forms of nylon, eg nylon 6 and nylon 66.
  • the composition may also comprise a filler, eg flame- retardant such as magnesium hydroxide which may be present in 45 to 65 per cent by weight of the composition, or if a lower standard of flame-retardancy is acceptable, the percentage may be 20 to 45.
  • a filler eg flame- retardant such as magnesium hydroxide which may be present in 45 to 65 per cent by weight of the composition, or if a lower standard of flame-retardancy is acceptable, the percentage may be 20 to 45.
  • the composition may contain additional fillers, for example, a ferromagnetic material such as strontium ferrite.
  • the composition may also contain reinforcing fibres, e.g. glass fibres, which may be present in up to 35% by weight depending on the amount of magnesium hydroxide or other filler which is present.
  • a plasticiser may also be used, eg butyl benzene sulphonamide which may be present in amounts of approximately 1.25 per cent by weight.
  • the first illustrative moulding composition was a formulation of 40 parts nylon 6, 60 parts magnesium hydroxide (Magnifin H5) , 0.3 parts calcium stearate (as a mould lubricant) , 1 part phthalimide, and 25 parts glass fibre (all parts by weight).
  • the composition was injection moulded into test discs which were subjected to tests in comparison with a comparison composition of the same formulation but with the phthalimide omitted.
  • the discs made from the comparison composition had very noticeable surface defects in the form of white marks covering the surface. It was considered that mouldings made from the comparison composition would have been unsaleable as their appearance would have been unacceptable to a customer.
  • the discs moulded from the first illustrative composition had noticeable surface defects but these were far less marked than in the comparison composition. It was considered that mouldings made from the first illustrative composition would have been acceptable to customers.
  • the discs made from the comparison composition gave a mean burn time of 3.6 seconds which is within acceptable limits.
  • a tensile strength test gave an average value of 120MPa
  • an elongation at break test gave a value of 1.1%.
  • a flexural strength test gave a value of 192MPa.
  • the second illustrative composition was the same as the first except that 2.5 parts by weight of phthalimide and 70 parts by weight of magnesium hydroxide were included. Discs injection moulded from the second illustrative composition were found to have no discernable surface defects in the form of white marks. The above- mentioned tests were repeated for the second illustrative composition. The mean burn time was measured as 1.5 seconds, the tensile strength as 121MPa, the elongation at break as 1.3%, and the flexural strength as 191MPa.
  • the first and the second illustrative compositions were both easier to mould, ie required less injection force, than the comparison composition.

Abstract

A moulding composition contains a polyamide, e.g. nylon 6 or nylon 66, and, optionally, a filler, such as magnesium hydroxide which acts as a flame-retardant. In order to reduce surface defects in the moulding, the composition also contains phthalimide.

Description

MOULDING COMPOSITIONS CONTAINING A POLYAMIDE
This invention is concerned with moulding compositions which contain a polyamide, e.g. nylon 6 or nylon 66, and is especially concerned with such compositions which contain a filler, eg magnesium hydroxide as a flame retardant.
Polyamides, such as nylons, are widely used for moulding components and, for some moulding applications, are mixed with a flame-retardant so that the moulded component exhibits flame retardant characteristics. Such applications include electrical lamp-holders, and switch housings.
Magnesium hydroxide is a flame retardant which has been suggested for use with nylon. This material, when subjected to a flame, decomposes endother ically with the liberation of water. Nylon containing magnesium hydroxide has, however, been found to be difficult to mould because of its high melt viscosity and, furthermore, it is found that the mouldings have obvious surface defects which render them unacceptable commercially. Such surface defects manifest themselves by the appearance of white patches on the surface of the moulding. Various attempts have been made to overcome this problem but without achieving complete success. The most successful previous attempt known to the applicants involves the addition of organic sulphonamide to the moulding composition (see GB 2,237,573A) but even this has not achieved total success.
It is an object of the present invention to provide a moulding composition containing a polyamide which produces mouldings which are substantially free of surface defects of the type referred to.
It is a further object of the invention to provide a moulding composition containing a polyamide and magnesium hydroxide which produces mouldings which are substantially free of surface defects of the type referred to.
The invention provides a moulding composition containing a polyamide characterised in that the composition also contains phthalimide.
Phthalimide is recorded in the Chemical Abstract Service Registry under number CAS 85-41-6.
A moulding composition according to the invention is found to produce mouldings with reduced surface defects. The composition is also found to be easier to mould making it possible to mould compositions with higher concentrations of fillers.
Preferably, the phthaimide provides 0.1 to 5 per cent by weight of the composition, eg 0.5 to 5 per cent. In some compositions, about 1 per cent of phthalimide is found to result in saleable mouldings, ie with an acceptable level of surface detects, and 2.5 per cent was found to result in substantially no discernable surface defects.
The polyamide may be nylon 6, nylon 66, nylon 6.12, nylon 6.10 or another suitable polyamide. The polyamide may also be a co-polymer of two forms of nylon, eg nylon 6 and nylon 66.
The composition may also comprise a filler, eg flame- retardant such as magnesium hydroxide which may be present in 45 to 65 per cent by weight of the composition, or if a lower standard of flame-retardancy is acceptable, the percentage may be 20 to 45. The composition may contain additional fillers, for example, a ferromagnetic material such as strontium ferrite. The composition may also contain reinforcing fibres, e.g. glass fibres, which may be present in up to 35% by weight depending on the amount of magnesium hydroxide or other filler which is present. ' A plasticiser may also be used, eg butyl benzene sulphonamide which may be present in amounts of approximately 1.25 per cent by weight.
There now follow detailed descriptions of two moulding compositions which are illustrative of the invention.
The first illustrative moulding composition was a formulation of 40 parts nylon 6, 60 parts magnesium hydroxide (Magnifin H5) , 0.3 parts calcium stearate (as a mould lubricant) , 1 part phthalimide, and 25 parts glass fibre (all parts by weight). The composition was injection moulded into test discs which were subjected to tests in comparison with a comparison composition of the same formulation but with the phthalimide omitted.
The discs made from the comparison composition had very noticeable surface defects in the form of white marks covering the surface. It was considered that mouldings made from the comparison composition would have been unsaleable as their appearance would have been unacceptable to a customer. The discs moulded from the first illustrative composition had noticeable surface defects but these were far less marked than in the comparison composition. It was considered that mouldings made from the first illustrative composition would have been acceptable to customers.
In a flammability test, the discs made from the comparison composition gave a mean burn time of 3.6 seconds which is within acceptable limits. A tensile strength test gave an average value of 120MPa, an elongation at break test gave a value of 1.1%. A flexural strength test gave a value of 192MPa. These tests were repeated using the discs made from the first illustrative composition. The mean burn time was 4.7 seconds (also acceptable), the tensile strength was 126MPa, the elongation at break was 1.0%, and the flexural strength was 192MPa. Thus, in all the tests, the first illustrative composition substantially equalled the comparison composition. The first illustrative composition was also easier to mould.
The second illustrative composition was the same as the first except that 2.5 parts by weight of phthalimide and 70 parts by weight of magnesium hydroxide were included. Discs injection moulded from the second illustrative composition were found to have no discernable surface defects in the form of white marks. The above- mentioned tests were repeated for the second illustrative composition. The mean burn time was measured as 1.5 seconds, the tensile strength as 121MPa, the elongation at break as 1.3%, and the flexural strength as 191MPa.
The first and the second illustrative compositions were both easier to mould, ie required less injection force, than the comparison composition.

Claims

A moulding composition containing a polyamide characterised in that the composition also contains phthalimide.
A moulding composition according to Claim 1, characterised in that the phthalimide comprises 0.1 to 5 per cent by weight of the composition.
A moulding composition according to either one of claims 1 and 2, characterised in that the polyamide is nylon 6.
A moulding composition according to either one of claims 1 and 2, characterised in that the polyamide is nylon 66.
A moulding composition according to any one of Claims 1 to 4, characterised in that the composition also comprises a filler.
A moulding composition according to claim 5, characterised in that filler is magnesium hydroxide.
A moulding composition according to any one of claims 1 to 4, characterised in that the composition also comprises a ferromagnetic material.
A moulding composition according to any one of Claims 1 to 7, characterised in that the composition also contains reinforcing fibres. A component moulded from a moulding composition according to any one of claims 1 to 8.
PCT/GB1995/000875 1994-04-19 1995-04-18 Moulding compositions containing a polyamide WO1995028439A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9407686A GB2288808A (en) 1994-04-19 1994-04-19 Moulding compositions containing a polyamide
GB9407686.6 1994-04-19

Publications (1)

Publication Number Publication Date
WO1995028439A1 true WO1995028439A1 (en) 1995-10-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1995/000875 WO1995028439A1 (en) 1994-04-19 1995-04-18 Moulding compositions containing a polyamide

Country Status (2)

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GB (1) GB2288808A (en)
WO (1) WO1995028439A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6361848B1 (en) * 1994-12-19 2002-03-26 Mitsubishi Denki Kabushiki Kaisha Organic and inorganic complex compound and switch using same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1536081A (en) * 1966-09-08 1968-08-09 Bayer Ag Polyamide molding compositions
JPS60232610A (en) * 1984-05-04 1985-11-19 旭化成株式会社 Molding material for electric part
GB2237573A (en) * 1989-11-03 1991-05-08 T & N Technology Ltd Flame retardant polyamides
EP0576951A1 (en) * 1992-07-03 1994-01-05 Bayer Ag Flame retardant polyamide moulding compositions

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3617731A1 (en) * 1986-05-27 1987-12-03 Bayer Ag FLAME RESISTANT POLYAMID

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1536081A (en) * 1966-09-08 1968-08-09 Bayer Ag Polyamide molding compositions
JPS60232610A (en) * 1984-05-04 1985-11-19 旭化成株式会社 Molding material for electric part
GB2237573A (en) * 1989-11-03 1991-05-08 T & N Technology Ltd Flame retardant polyamides
EP0426243A1 (en) * 1989-11-03 1991-05-08 T&N TECHNOLOGY LIMITED Polyamide moulding compositions
EP0576951A1 (en) * 1992-07-03 1994-01-05 Bayer Ag Flame retardant polyamide moulding compositions

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 8601, Derwent World Patents Index; Class A23, AN 86-004627 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6361848B1 (en) * 1994-12-19 2002-03-26 Mitsubishi Denki Kabushiki Kaisha Organic and inorganic complex compound and switch using same
US6414067B2 (en) 1994-12-19 2002-07-02 Mitsubishi Denki Kabushiki Kaisha Organic and inorganic complex compound and switch using same

Also Published As

Publication number Publication date
GB9407686D0 (en) 1994-06-15
GB2288808A (en) 1995-11-01

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