JPS585938B2 - Asbestos flame-resistant polyalkylene terephthalate resin composition without clamping properties - Google Patents

Description

[Detailed description of the invention] The present invention relates to molding resins with improved uniformity.

The molding resin of the present invention with improved color and physical properties consists of an intimate mixture of the following components:

That is, (1) polypropylene terephcrate or polybutylene terephthalate polymer: (2) flame retardant; (
3) Asbeth l-; (4) Reinforcing filler (which may or may not be present); (5) Other additives such as lubricants and nucleating agents, which make up 2% or more of the above polymer. is 6
It is present in the form of a powder (passes through a 30 mesh screen) with a particle size of less than 0.00 microns.

Due to the improved uniformity of the composition of the present invention, the stability of physical properties and color fastness are significantly improved compared to molding compositions produced using the same raw materials without using powder.

Recent studies have shown that polypropylene terephthalate and polybutylene terephthalate are superior to polyethylene terephthalate in many properties.

For example, polypropylene terephthalate and polybutylene terephthalate can be formed and processed at lower temperatures and have shorter cycle times in molding.

Additionally, and very importantly, unlike polyethylene terephthalate, these resins do not require the presence of a nucleating agent to promote crystallization.

In fact, when nucleating agents or mold release agents are added to polypropylene terephthalate and polybutylene terephthalate molding resins, as described in Patent Application Continuation No. 854,259, the surface properties of the resulting molded articles deteriorate.

In other words, the surface gloss deteriorates, wrinkles appear, and smoothness is lost.

namely, these polypropylene terephthalate and polybutylene terephthalate resins (these resins, along with polyethylene terephthalate, were first disclosed in U.S. Pat. No. 2.46
5.319) solves processing problems associated with polyethylene terephthalate and other polyalkylene terephthalates.

Equally important, these molding resins are very well balanced in their operating properties.

Therefore, it can be said that polypropylene terephthalate and polybutylene terephthalate are suitable for a wider range of practical applications than polyethylene terephthalate because of their excellent operability and physical properties.

These molding resins have one important drawback, however.

That is, they are flammable. The development of self-extinguishing molding grade polypropylene terephthalate and/or polybutylene terephthalate resins is therefore of great practical importance.

Polyalkylene terephthalate moldings are often used in household and other electrical appliances, where these appliances must not be ignited by sparks or by heat from the appliance itself.

Various flame retardant additives have been developed to impart self-extinguishing properties to polypropylene terephthalate and/or polybutylene terephthalate resin compositions.

Additionally, reinforcing agents such as asbestos are often used to inhibit dripping of burning particles.

A significant drawback of the use of asbestos fibers is that they tend to agglomerate, i.e. form balls or knots in the presence of flame retardants, significantly reducing their physical properties and thus rendering the surface uniformity impractical. and loss of color.

The object of the present invention is to have an intrinsic viscosity of about 0.7 with the following properties.
5-1.5 dl/g polyalkylene terephthalate (
In particular, the object is to provide molding resins (polypropylene terephthalate and polybutylene terephthalate).

These resins have improved physical properties, have surface and color uniformity desirable as commercial products, are self-extinguishing, and have non-dripping properties due to the addition of asbestos fibers.

The suppression of agglomeration in flame-resistant polyalkylene terephthalate resin compositions is based on the weight of the polymer in the composition to be molded.
This is achieved by adding more than wt% of powdered resin.

Powdered resin means a particle size smaller than 600 mesh, ie, one that passes through 30 screens.

Due to improved uniformity and dispersibility, not only color tone and surface properties but also physical properties were improved as well.

The base of the resin of the present invention is a polyalkylene terephthalate polymer selected from polypropylene terephthalate and polybutylene terephthalate.

These polymers are described in U.S. Patent No. 2,465,319
terephthalic acid and is obtained by reaction of dibasic acids of terephthalic acid or dialkyl esters of terephthalic acid (in particular dimethyl terephthalate) with diols having 3 and 4 carbon atoms.

Suitable diols are 1,3-propanediol, 1,4-
These include butanediol, 1,3-butanediol, 1,2-propanediol, 1,2-butanediol, 2,3-butanediol, and the like.

In the production of the polymer of the present invention, ie polypropylene terephthalate or polybutylene terephthalate, a suitable bis(hydroxyalkyl) terephthalate is synthesized as an intermediate.

Bis(hydroxyalkyl) terephthalates are obtained by reacting dialkyl esters of terephthalic acid (the alkyl group having 1 to 7 carbon atoms) with twice the mole of the above-mentioned diols.

In the reaction, it is preferable to use an excess of diol, that is, about 1.5 mol in excess per 1 mol of terephthalate.

The first transesterification reaction thereby proceeds more quickly and completely.

The esterification reaction is carried out under heating, normal pressure, reduced pressure or increased pressure.

Usually the preferred temperature is within 250°C of the boiling point of the reaction mixture.

Once the polymer paste is manufactured, additives such as colorants, plasticizers, stabilizers, hardeners, etc. may be added to the present invention by dry blending, melt blending, extruder blending, hot roll or other methods to improve appearance and properties. Mix intimately into molding resin.

As already mentioned, these new resins have one major drawback:
own.

It is flammable and upon combustion drips significant amounts of flaming particles.

There are two methods for measuring the combustion characteristics of thermoplastic resins.

One of them is L. O. I or the limiting oxygen index (
The second method is the Vertical Combustion Test, which is the "SE-0";"SE-I" and "SE-■" test proposed by the Underwriters Institute. ” (UL-94).

UL-94 vertical combustion test method is Underwrite I
This is a method developed by the /s Research Institute, in which one end of a sample 5 inches long, 1/2 inch wide, and 1/16 or 1/8 inch thick is held with a clamp, fixed vertically, and burned. This is a method of testing.

The bottom edge of the sample is located 12 inches above the horizontal cotton absorbent layer.

The flame of a Bunsen burner having an 8/3 inch diameter is adjusted to a length of 3/4 inch and placed so that the tip of the flame is 3/8 inch below the bottom edge of the suspended sample.

The test flame is held for 10 seconds and then removed to observe the flame durability of the sample and the spread of combustion. If combustion stops within 30 seconds after burner removal, the burner is immediately placed under the sample again.

If the combustion retention time is 10 seconds or more and 30 seconds or less, the sample is ranked as "SE-0", and if the combustion time is 60 seconds or less, it is ranked as "SE-II".

The second sample is further tested.

A second sample is tested as above but with the addition of “S”
10 seconds after the second removal of the test flame for samples of the "E-0" class, and 30 seconds for samples of the "SE-11" class, whether or not it has the ability to ignite dry absorbent cotton. or will be tested.

A sample ranked as "SE-0" has the following characteristics.

That is, A: combustion with flame after application of test flame is 10
There are no samples that last longer than seconds.

B The total combustion time after 10 ignition operations for 5 samples does not exceed 50 seconds.

C: There is no sample that continues to burn up to the position of the holding clamp.

D. No burning droplets capable of igniting the dry absorbent cotton located 12 inches directly below the test specimen.

E. There are no samples that continue to burn for more than 30 seconds after the second removal of the test flame.

F Test: There is no sample that has the ability to ignite the absorbent cotton for 10 seconds or more after removing the flame.

The flame resistance of polyalkylene terephthalate is disclosed in U.S. Patent No. 347,514 (filed in 197343),
, 823 (filed on June 16, 1970), both filed by the same applicant as the applicant of the present invention] by adding well-known additives such as those described in US Pat. No. 3,624,24.

In compositions without fillers, preferred additives are aromatic bromine compounds that are stable at the melt processing temperatures of the polyalkylene terephthalate and decompose at its combustion temperature, and compounds containing metals selected from arsenic, antimony and bismuth. It is.

Here, the molar ratio of the effective metal to the available hydrogen in the metal-containing compound is about 1:2-1:4, and the amount of the metal-containing compound and the aromatic bromine compound is about 0.5-1:4 based on the total composition. 17.5wt
%.

The composition includes a reinforcing filler and a flame retardant, which is stable at the melt processing temperature of the polyalkylene terephthalate and decomposable at the combustion temperature of the polyalkylene terephthalate, and an aromatic halogen compound and arsenic; It consists of a metal-containing compound selected from antimony, bismuth and phosphorus, with a weight ratio of available halogen to available metal of about 0.3-4.

The flame retardant is present in about 1-30 wt% of the total composition.

Particularly preferred flame retardant compounds are pentabromotoluene; tetrabromofucuric anhydride; tetrachlorofucuric anhydride; 3,5,3',5'-tetrabromobiphenyl ether, 3,5,3',5' -tetrachlorobiphenyl sulfide; 3,5-dichloro-3,5'-dibromobiphenyl sulfoxide; 2,4-dichloro 3',
4',5'-dribromophenylmethane; decabromobiphenyl ether, 2,2',4,4',6,6'-hexachlorobiphenyl;2,2',4,4',6,6'
-hexabromobiphenyl;3,5,3.3'-tetrabromo-2,2'-bis(4,4'-didimethoxyphenyl)propane, and the like.

When these compounds are mixed with compounds containing phosphorus, arsenic, antimony and bismuth, especially oxides, of which antimony trioxide is particularly preferred, a complementary flame-retardant effect is obtained.

As mentioned above, if desired, a toughening agent can be incorporated into the polymer or into the monomer so long as it does not affect the reaction.

A typical example of a filler is glass fiber (short and long fibers)
, mica, silicic acid, calcium, cellulose fibers, metal powders, etc., and mixtures thereof.

Strongly the amount of filler is about 2-80w for the total molding composition
t% is preferably about 5-60 wt%.

The intrinsic viscosity of polypropylene terephthalate and polybutylene terephthalate molding resins is about 0.75-1.5 dl/g, preferably about 0.85-1, as measured at 25°C in a melt of 8% orthochlorophenol based on the weight of the polymer.
．． It is 4 dl/g.

Stabilizers are also added if necessary to improve long-term stability.

In such cases from about 0.01 to about 1 for the total composition.
．． 0 wt% preferably about 0.05-0.3 wt% substituted or unsubstituted alkylene bis fatty acid amide is added.

and the alkylene group has 2-12 carbon atoms,
(preferably 2-6), the fatty acid group has 2-30, preferably 12-18 carbon atoms.

Representative examples of preferred substituents for fatty acid groups are hindered phenols as antioxidants.

Particularly preferred compounds for the purposes of this invention are ethylene bis stearamide, hexene bis lauramide, and ethylene bis-3(3.5-di-t-butyl, 4-hydroxyphenol) propanamide.

No. 350, co-pending U.S. patent application Ser.
．． 249.

About 0.2-50wt in the total composition for flame resistant compositions to suppress flame dripping and thereby ensure SE-O.
Asbestos is added preferably in a proportion of about 0.5-30 wt%.

Example 1 1200 g of dimethyl terephthalate and 900 g of 1,4 butanediol are mixed with a suitable catalyst such as zinc antimony acetate monotrioxide or lead oxide zinc monoxide as described in US Pat. No. 2,465,319.

Then, the temperature is raised to approximately 200°C.

Once approximately 80% of the methanol has been removed, vacuum is applied to the system and the temperature is increased to 240-250°C.

When the intrinsic viscosity of the resin composition reaches a target value, the vacuum is broken.

If a flame retardant is to be added, mix it in at this point.

The whole is then stirred for a further 5-10 minutes, removed and chipped in the usual manner.

If blending glass fibers with the polymer, add the fibers and mix with molten polybutylene terephthalate for 1 minute;
It is then pumped through a 1 inch single screw extruder equipped with a conventional die.

Extruder and die temperatures are approximately 500-510°F.

The extruded filamentous mixed proboscis is crushed to pass through a large screen (4 mesh or less).

All of the above samples were shaken and tested for approximately 61 minutes.

The sample of Example 2, a composition consisting only of PBT chips, antimony trioxide, and asbestos, shows no tendency to clamp, and the sample of Example 3, in which glass fibers are added, also shows no tendency to clamp.

In the sample of Example 4, significant clamping was observed simply due to the addition of decabromobiphenyl ether.In the sample of Example 5, in which glass fiber was added to the sample of Example 4, significant clamping due to the flame retardant was also observed.

Examples 6 and 7 show compositions according to the invention in which a portion of polybutylene terephthalate was added in powder form, and it was found that not only was no clamping observed, but the homogeneity was very high.

Moreover, the composition of Example 6, which does not contain glass fibers but consists only of asbestos and flame retardants, has very good performance against clamps.

Even when other flame retardants such as pentabromotoluene and tetrabromophthalic anhydride were used, significant clamping properties were observed in the same formulations as in Examples 4 and 5, but PB
The occurrence of clamping was suppressed by adding about 45 wt % powdered PBT instead of the T-chip.

Similar results were obtained when polypropylene terephthalate was used instead of PBT.

Although the present invention has been described above using Examples, the present invention is not limited thereto.

The embodiments of the present invention and related matters are as described in Mitsuru.

(1) The composition according to claim 1.

(2) Asbestos is approximately 0.2-50w based on the total composition
t% of the improved resin composition of paragraph (1).

(3) Flame retardant additive is approximately 1-30wt based on the total composition
% of the improved resin composition of paragraph (1).

(4) The flame-resistant additive is an aromatic bromine compound that is stable at the melt processing temperature of the polyalkylene terephthalate and decomposable at the combustion temperature of the polyalkylene terephthalate, and a compound of a metal selected from the group consisting of arsenic, antimony, and bismuth. The ratio of the available metal in the metal compound to the available bromine in the bromine compound is approximately 1:2-1:4 by weight, and the amounts of the metal compound and the bromine compound are approximately 1:2 to 1:4 in the total composition. The improved resin composition according to item (3), characterized in that the content is about 0.5-17.5 wt%.

(5) The improved resin composition of item (1) further containing a reinforcing filler.

(6) The reinforcing filler is approximately 2-80 wt% based on the total composition.
The improved resin composition of item (5) that exists.

(7) The improved flame retardant composition of paragraph (3), further comprising about 2-80 wt% (based on the total composition) of reinforcing filler.

(8) The flame retardant additive is selected from the group consisting of aromatic bromine compounds and arsenic, antimony, bismuth, and phosphorus that are stable at the polyalkylene terephthalate melt processing temperatures and decomposable at the polyalkylene terephthalate combustion temperatures. The improved resin composition of paragraph (7), comprising a metal-containing compound, wherein the weight ratio of available bromine in the brominated compound to available metal in the metal compound is about 0.3-4.

(9) The improved resin composition of item (1) further containing a substituted or unsubstituted alkylene bis fatty acid amide.

(10) In the alkylene bis fatty acid amide, the alkylene group has about 2-12 carbon atoms, the fatty acid group has about 2-30 carbon atoms, and the fatty acid amide has about 0.01-
1.0 of the improved resin composition of paragraph (9).

(11) The improved resin composition according to item (10), wherein the substituted or unsubstituted alkylene bis fatty acid amide is ethylene bis stearamide or hexene bis lauramide.

(12) The improved resin composition of item (7), wherein the reinforcing filler is glass fiber.

(13) The improved resin composition of item (7), wherein the reinforcing filler is calcium metasilicate.

(14) The improved resin composition of item (7), wherein the reinforcing filler comprises a mixture of glass fiber and calcium metasilicate.

Claims (1)

[Claims] 1 Intrinsic viscosity approximately 0. 75-1. A polyalkylene terephthalate molding resin composition with significantly improved uniformity and surface properties comprising an intimate mixture of 5 dl/g of a polyalkylene terephthalate selected from the group consisting of polypropylene terephthalate and polybutylene terephthalate; a flame-retardant additive; and asbestos. An improved resin composition characterized in that the enhancement comprises intimately admixing 2% or more of polyalkylene terephthalate, based on the weight of the resin, present as a powder with a particle size of less than 600 microns. thing.