JPS5962659A - Thermoplastic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to thermoplastic polyester compositions that are particularly useful in injection molding operations conducted at relatively low mold temperatures.

Polyethylene terephthalate (PET) has long been known to have excellent physical properties, such as resistance to chemical attack, and desirable mechanical and electrical properties. Despite these excellent physical properties, PET is not always injection molded as relatively high mold temperatures, e.g. 120°-140°C, have to be used to ensure good moldability. It was not the material of choice for this purpose. Any attempt to use lower mold temperatures, e.g. 100° C. or lower, has been unsuccessful because, firstly, the molded article would stick in the mold and could often be removed only with great difficulty. The result was that the injected material could not be molded.

To avoid this processing drawback, molders are using more expensive materials such as polyethylene terephthalate (PBT).
This poly(alkylene terephthalate) can be easily molded even when using mold temperatures as low as 60°C. The ability to use lower mold temperatures for PBT reduces the time required to cool the injection molded article to a temperature where it can be removed from the mold from 1200 to 140 °C. This is significantly shorter than the cooling time required before it can be removed. This shorter cooling time of PBT results in shorter processing cycle times and faster article production rates, so there is economic justification for its use despite its higher unit cost.

A welcome contribution to this technology is the relatively low mold temperature (
An example would be a PET composition that can be injection molded at temperatures (100° C. and below) to yield articles exhibiting improved moldability properties, such as improved mold release and robust physical properties.

In accordance with the present invention there is provided a thermoplastic, injection moldable composition having improved moldability comprising: (a) polyethylene terephthalate; and (b) a low volatility paraffinic hydrocarbon; and (C) at least In order to improve the releasability of articles injection molded from the composition from the injection mold at humidity as low as 96°C (
b) containing a homogeneous mixture of paraffinic hydrocarbons and cooperating auxiliaries.

Due to the cooperation between components (b) and (01) above, this composition does not encounter excessive sticking and has a relatively low mold temperature (
For example, it can be molded at temperatures ranging from about 50'O to about 100°C.

Of course, if desired, the compositions of the present invention can be injection molded at higher mold temperatures (eg, from about 100° to about 150°C).

A further feature of the invention is that the composition may additionally contain reinforcing fillers such as glass fibers alone or in combination with particulate mineral fillers. Other additives such as flame retardants, impact modifiers, and the like may also be used in the composition.

The polyethylene terephthalate used herein is preferably a monopolymer PET, although crystalline RET copolymers can also be used. Examples of useful PET copolymers include at least 80 mole percent of the repeat units derived from terephthalic acid and ethylene glycofur, with the remainder (20 mole percent or less) derived from other known acid and/or glycol components. It is a copolymer containing Typical acid components are phthalic acid, isophthalic acid, and naphthalene1
゜4- or 2,6-dicarboxylic acid, diphenyl-4,
4'-dicarboxylic acid, diphenyl ether-4,4'-
dicarboxylic acids, azopic acid, sepacic acid and their halogenated (stamped or brominated) counterparts. Glycol ingredients are diethylene glycol and neopentyl.
Glycol, cyclohexane dimetatool, 2,2-bis(4-hydroxyphenyl)propane, 1. ro-propanediol, 1,4-butanediol, dibromoneopentyl glycol, bis(2-hydroxyethyl) ether to tetrabromobisphenol, tetracylomopara-xylene glycol and the like.

The polyethylene terephthalate used herein may be virgin PET or recycled PET. The PET used in the compositions of the present invention should also be injection moldable and therefore generally 0.3 as low as 0.4 and preferably 1.2
between about 0;5 and 1.0, more preferably between about 0;5 and 1.0. For most injection molding applications, polyethylene terephthalate with an I,V in the range of 0.4 to about 9 is most preferred.

Low volatility paraffinic hydrocarbons suitable for use in the present invention include mineral oil and paraffin wax. Mineral oil is liquid petroleum (1quid petroleum),
Liquid paraffin, white mineral oil
It is a liquid paraffinic hydrocarbon known variously as paraffin oil) and paraffin oil. The official trademark for such products is KAYDOL 5ALBO.
LINE.

NUJOL, PAROLEINE, 5AXOL
, AI) EPSINE OIL and GLYMOL
including.

The preferred paraffinic hydrocarbon utilized in the compositions of the present invention is mineral oil. Particularly desirable mineral oils are: (a) 0.05 at 100OF'(37.8°C);
(b) a specific gravity within the range of 0.818 to 0.905;
and (c) 0°F (-18°C) to lso raw (-1°C)
and (a) a pour point within the range of 280°F' (138°C) to 420°F (2
It has a flash point in the range of up to 16°C).

A particularly preferred mineral oil is 10 (11°F (37,8°C)
Viscosity within the range from 0.265 to 0.275 m'' at 7 o'clock, specific gravity within the range from 0.869 to 0.885, approximately OoF' (-18°O) Flow fjt + point Oyohi 420°F (216°C). An example of such a mineral oil is KAYDOL.

Various mineral oils suitable for use in the present invention - commercially available 08oneborn Division, W
itc.

Chemical Corporation 1277
Park Avenue 1New York,
N, Y, 10017 is KAYDOL, ○RZOL.

() Mineral oil with the product names LORIA 1 and PROTOL; RUDOL, ERVOL, BENOL
, IBLANDOL 1CARNATION and KL
Light mineral oil under the product name EAROL; and SEMTO
L 100, SEMTOL 85 and SEMTOL
We supply industrial grade white oil under 70 product names. Amoco Oil Company, Che
mical Division.

2 D D East Randolf 5treet
%Chicago, Illinois60601 35 USP, 31 USP121 USP.

i F3 USP, 15 NJ”, 1 [) NF
We supply white mineral oils under the product designations N9N17', 7NF, 5NF, 9T and 8T.

280°F' (158°C) to 420'F'(21<
Mineral oils having flash points in the range up to 674° F' (1900 C) can be utilized in the compositions of the present invention, although processing considerations related to the volatility of mineral oils dictate that flash points higher than 674° F' (1900 C) It is advantageous to use a mineral oil having a

Wax XL-165 is American Hoec
hstCorporation, Chemical
and Plastics Division.

Wax Department 5Route 202
-206 Nortb.

Somerville, New Jersey 0
A product name for paraffin wax available from 8876: (a) a freezing point within the range of 160'F (71,1°C) to 165°F (73,9°C); and (b) 167 °F (75°C) or lSI+172″F (
and (c) a dropping point within the range of 170'F (76,7°C) to 175°F.
It has a melting point in the range of (79,4°C) years old.

The compositions of the invention preferably contain 0 per 100 parts of PET.
．． paraffinic hydrocarbons (e.g., mineral oil) in the range of 5 to 12 parts and 0.00 parts per 100 parts of PET.
with an amount of auxiliary agent ranging from 0.05 to 5 parts. Most preferably, the amount of these ingredients used is 100 parts of PET.
2 to 8 parts of paraffinic hydrocarbons and 0
．． Within the range of 1 to 6 parts of adjuvant.

Highly preferred compositions of the invention are those in which the auxiliary agents have a synergistic effect. Synergistic effects are observed to be exhibited by the use of alkali and alkali metal salts of aliphatic monocarboxylic acids, alkali metal salts of aromatic carboxylic acids, alkali metal salts of carboxylic acids, minerals, and the like. Preference is given to the alkali metal salts sl-IJum salts and the alkaline metal salts calcium salts. Examples include, but are not limited to: formic acid, acetic acid, propionic acid, butyric acid,
Valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, valmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosanoic acid , behenic acid, tricosanoic acid,
Tetracosanoic acid, pelargonic acid, cerotic acid, montanic acid, methacrylic acid, acrylic acid and the like; sodium and potassium base; stearic acid and the like; benzoic acid, tolylat-t-butylbenzoic acid, salicylic acid,/manililic acid , protocatechuic acid, veratrum acid, gallic acid, phthalic acid, isofucuric acid, telefucuric acid, pomofucuric acid and the like; sodium and potassium salts; sodium carbonate, potassium carbonate, talc and the like.

Soaps that can be purchased in the market, such as IVORY SNOW and IVORY SOAP (these are manufactured by Ohio, Ci
ncinnati's Procter and ()am
ble Company) may be useful as a synergistic aid.

Lithium, cesium, and rubidium salts are not available for purchase and are not economical.

Less preferred are sodium of mildly disabled aliphatic monocarboxylic acids such as oleic acid, linoleic acid, linoleic acid, norolmitoleic acid, citric acid, erucic acid, and the like. Or you can use potassium salts.

Other useful auxiliaries include non-limiting ζ, nitrogen, ionomer resins, and ionomer resins with alkali metal cations such as (salts) having melt flow index of 2.8 and SURLYN 1. Ionomer resins such as Type 605 (this is E.1.du Pont de
Nemoursand Company), contains nogular hydroxybenzoic acid and zinc stearate.

Preferred salts are sodium acetate, sodium stearate, sodium benzoate, sodium chloride,
These are sodium montanate, starch lucium and talc.

Stearate can be purchased from several sources; for example, Witco Chemical C.
organization.

Organic Division, New Year
Sodium stearin T-1 or heat stable grade (Hea
t 5table grade).

As previously mentioned, other additives may also be utilized in the compositions of the present invention. For example, it is most useful if the composition further includes reinforcing fillers. Depending on its nature, this filler increases the strength and impact properties of the PET composition. In fact, the use of reinforcing fillers is often required by most injection molded PETO industrial applications today.

In general, any reinforcement can be used, such as fibers, voice cars, or platelets of aluminum, iron or nickel, and similar metals.
t), and non-metals such as ceramics, carbon filaments, silicates, asbestos, titanate whiskers, quartz, glass flakes and fibers, and the like. A sufficient amount of reinforcing filler is required to provide at least some reinforcement, but generally the filler is added in an amount of 1 part per 100 parts of unreinforced polyethylene terephthalate resin.
It will contain from 0 to 160 copies. Unreinforced PET 1
TTL fillers ranging from 60 to 140 parts per 00 parts, particularly glass fibers, are preferred as such compositions have particularly desirable properties. From the viewpoint of ease of injection molding, the reinforced compositions of the present invention, particularly those using glass fibers, are suitable for use in unreinforced polyethylene terephthalate resins.
It is preferred to include the filler component in an amount within the range of 60 to 90 parts by weight per 00 parts by weight.

Among the various fillers that can be used in the compositions of the present invention, a preferred reinforcing filler is glass.

Most preferred is the use of fibrous glass filaments of relatively soda-free lime-aluminum borosilicate glass. This is known as rEJ glass. The length of the glass filaments and how they are bundled into fibers and the bundled fibers are then made into threads, etc. are not critical to the invention. But about 0.5175
The use of cTL-length glass strands has proven advantageous. Not to mention the amount of breakage of the strands during compounding which would result in further length reduction in the final injection molded article.

Other additives may also be used in the compositions of the present invention to achieve desirable properties of the glaze in the final injection molded article. For example, flame retardants may be added if the end use of the product requires that the product may be exposed to sources of combustion.

To improve impact resistance, impact modifiers can be added to the compositions of the invention. For protection against thermo-oxidative degradation, conventional amounts of stabilizers are added to the compositions of the invention, preferably in amounts from o, o o i to 0.5 parts per 100 parts of the weight of the unstabilized composition. can be added to. Depending on the end use of the molded product, UV absorbers, lubricants, antistatic agents, colorants, antibacterial agents, blowing agents, etc. can additionally be added to the compositions of the invention.

The compositions of the invention are prepared by mixing the various components in a compounder, such as a tumble mixer or a Hen5chel mixer, and extruding the mixture into an extruder, such as a twin screw mixer.
Compound in an 8 mm Werner-Pfleiderer extrusion die and then cut the extruded material into pellets. The resulting product is suitable for injection molding operations. It is believed that the compositions of the present invention can be successfully injection molded at temperatures below 100°C, with acceptably short cycle times and with physical properties that are commercially attractive or at least have commercial potential. It must be a molded article that exhibits the properties

The invention is illustrated in the following examples, which should not be construed as limiting.

EXAMPLES The various PET compositions of this example were prepared by mixing the ingredients to form a premix and compounding the premix in a single screw extrusion mode at about 500'F (260°C) (rA degrees). , and the pellets were formed into articles by a reciprocating screw set injection molding machine.

The injection mold was suitably shaped and dimensioned to provide an article having the shape shown in the accompanying figure, which is a top plan view of the article. The mold utilized was a central sprue mold with a stationary sprue side and a movable cavity side. The article produced by the mold as shown in the drawing has a number of runners, labeled "A", which have various test pieces at their ends. Extending from the center of the runner network is a conventional tapered sprue. The two specimens are rectangular bars and are designated by the letters rBJ. These rBJ specimens are approximately 6 inches (15,24 cm) long, -inch (
1,27C1n) wide and 1 inch (0,635Cr
IL) thickness.

The test piece labeled "C" in the figure is a rectangular bar with a length of 2-inch (6,35C) rL), -in2

It is 2 inches (1,27 C1rL) wide and 1 inch (0,3175 cm) thick. Two "dog bone" shaped specimens are labeled "D" and are used for tensile strength testing. They are about 6↓ inches (16,5c++t) long, -inches (0
, 3175CrIL) and the width at each end -inch (1,905C1rL) and the width at the middle part -inch (1,27C7n). The width of inch (6,985 儒) and the width of 1 inch (0,3
The thickness is 175 crn). Runner Yoshi Suzoru has a cross-sectional width of approximately 1 inch (0-9525 aa).

This geometry for the test articles was chosen for the complexity and yield of the test specimens, which are used in accordance with well-recognized standard tests. The complexity of the article shape also appeared to be sufficient to provide a good predictor of the moldability performance of the composition when used to make typical art articles.

The polyethylene terephthalate, glass and other ingredients used in the various compositions of this example were as follows: Polyethylene terephthalate (PF, T);
oodyear Tire and Rubber C
From company; Vituf 5901-Crystalline PET
60% I) 0 when measured at 25°C in a solvent consisting of phenol and 40% tetrachloroethane.
．． It has an intrinsic viscosity of 59.

Fiberglass Carp, Owens-Co
rningJ'iberglas 419 AA (-
Inch C0,4766 α Chopped Strand] M-Mineral Oil; 5oneborn Division,
Witc.

Chemical Corporation, 277
Park Avenue, New York,
N, Y, 10017 to KAYDOL product name; AmcO○11Company, Comme
rcial Division 200East Ra
ndolph 5treet, chicago.

1111nois 60601, from 5 NJi' and 35 Sodium stearate by USP product name; Witco Chem
From icalCompany; T-1 or Heat
5table class.

The moldability of a composition is determined by the number of "sticks" (i.e., the number of shots that were performed with a given pg'r composition) (i.e., the number of injections) (i.e., the molding cycle was stopped and the test molded). It was evaluated by measuring the number of times a piece had to be removed from the mold. In severe cases, removal of the sticky area required scraping or chiseling; in less severe cases, removal was possible by hand.

10111;]? +5 ethylene terephthalate,
46 parts/100 parts PET waste fiber, 6 parts/100 parts P
ET's 35 USP Amoco White Oil
and 0.5 parts/10 parts PgT stearic acid I-
The moldability was determined to be 6 viscosity 1/16 shot for the compositions of the present invention containing IJum.

Tables 1 (Examples 1-9) and 1 (Example 16) report the moldability properties of other compositions of the invention.

Tables 1 (Comparative Examples 1O-12), 1 (Comparative Examples 14) and 1V (Comparative Examples 15 and 16) report the moldability properties of compositions not according to the invention.

In all moldability studies, the mold temperature was approximately 200'
F (96°C).

All parts shown in Table 1-1 are by weight.

In all, synergistic results were obtained. Most, if not all, other compositions of the invention will provide similar synergistic results, although no further testing has been performed on them to date.

The data shown in Table V illustrate the good balance of physical properties exhibited by articles injection molded from the compositions of this invention. Here again the mold temperature is about 200°F (93°
C). Injection molded test bars were obtained from the selected compositions and tested according to ASTM procedures to evaluate the physical properties shown in Table V. The A8TM designation numbers for the procedures used were as follows: Specific Gravity...D792-66 (1975) Tensile Yield, and 'Tensile Modulus...D638-77a Flexural Strength, and Flexural Modulus...D790-71 (197
8) Izot impact: D256-78 Heat deflection temperature: D648-72 (1978) Rotwell hardness: D785-65 (1976).

[Brief explanation of the drawing]

The attached drawing is a top plan view showing the outline of the relationship between the runner, the thread loop, and the mold of the injection molding machine used in the embodiment of the present invention, and the symbols in the drawing represent the following: A: runner; B, C, E: Test piece, D: Test piece for measuring tensile strength. Agent Akira Asamura

Claims (1)

[Scope of Claims] (1) A thermoplastic composition that can be injection molded at relatively low mold temperatures, the composition comprising: (a) polyethylene terephthalate; and (b) a low-volatility paraffinic hydrocarbon system; and (C) to improve the release of articles injection molded from the composition from the injection mold at temperatures as low as at least 96°C (
Thermoplastic compositions comprising a homogeneous mixture of co-operative auxiliaries with the paraffinic hydrocarbons of b). (2) The composition according to claim (1), wherein the paraffinic hydrocarbon is mineral oil. (3) the mineral oil has a viscosity of about 0.86 at 68°C within the range of about 0.265 to 0.273 m2/hr;
Specific gravity within the range of 9 to about 0.885, about -18°C
A composition according to claim 2, having a pour point of about 215.5°C and a flash point of about 215.5°C. (4) The composition according to claim (1), wherein the auxiliary agent is an alkali metal salt of an aliphatic monocarboxylic acid. (5) The composition according to claim (4), wherein the alkali metal salt is a sodium salt. (6) The composition according to claim (4), wherein the salt is sodium stearate. (8) The composition of claim 1, wherein said auxiliary agent is sodium carbonate. Viscosity of about 0.81
A liquor having a specific gravity within the range of 8 to about 0.905, a pour point within the range of -18°C to 11°C, and a flash point within the range of 168°C to 215.5°C. A composition according to claim (2). (9) said paraffinic hydrocarbon system is present in an amount ranging from 5 to 12 parts by weight per 100 parts by weight of said polyethylene terephthalate, and said auxiliary agent is present in an amount ranging from 5 to 12 parts by weight per 100 parts by weight of said polyethylene terephthalate; 0 per part
．． A composition according to claim 1, wherein the composition is present in the range from 0.05 to 5 parts by weight. QO) A composition according to claim (1), wherein said composition further comprises a reinforcing filler. αυ The composition according to claim 00), wherein the reinforcing filler comprises glass fibers. (17J) (a) is polyethylene terephthalate having an intrinsic viscosity of from 0.4 to 0.9, measured at 25°C in a solvent consisting of 60% by weight phenol and 40% by weight tetrachloroethane. The composition according to claim (1). ([3) The thermoplastic composition according to claim (1), which can be injection molded at a relatively low mold temperature, wherein the composition: (a) 0.0% as measured at 25°C in a solvent consisting of 60% by weight (a% by weight of phenol and 40% by weight of tetrachloroethane).
(b) a low volatility paraffinic hydrocarbon; and (C) an article injection molded from the composition at temperatures as low as at least 96°C; (b) an auxiliary agent which cooperates with the paraffinic hydrocarbon to improve the release properties from the injection mold; and (d) an amount of from 60 to 90 parts by weight per 100 parts by weight of polyethylene terephthalate. A thermoplastic composition comprising a homogeneous mixture of glass fiber reinforced fillers present.