Title of Invention

AN INJECTION-MOLDING COMPOSITION COMPRISING A TALCUM REINFORCED PROPYLEN POLYMER

Abstract (57) Abstract: The injection-molding composition of the invention based on a talc-reinforced propylene polymer contains an additive combination of glyceryl monostearate plus fatty acid dialkanolamide in a mixing ratio in the range from 1:1 to 3:1 and a total amount of up to 1.5 % by weight, based on the weight of the propylene polymer.
Full Text




Polypropylene molding composition containing an anti¬static agent and having low-fogging properties
The invention relates to a polypropylene molding composi¬tion containing an antistatic agent. Surfaces of moldings produced therefrom therefore have only low dust attrac¬tion and for this reason have a low susceptibility to soiling. At the seune time the material has low emissions and thus has low fogging values. The molding composition of the invention can be processed by means of the customary processing methods such as injection molding, extrusion and extrusion blow molding.
Motor vehicle interior trim components such as coverings of A, B, C columns, dashboards, door linings, seat coverings, glove compartments and consoles are produced on an industrial scale by injection molding from thermo¬plastic polymers. For cost reasons, talc-reinforced polypropylene is mainly used in this field of applica¬tion. Since the parts are present in a visible region, high demands are placed on the visual surface q[uality. However, undesireible and unsightly soiling of the surfaces by dust deposition frequently occurs because of the low surface conductivity of the polypropylene and as a result of electrostatic charging. Typical dust patterns (crow's feet) thus become visible. These undesnrsible crow's feet can occur both during the production process of these moldings and also during later assembly or normal use. Since the soiling gives a visual impression of lower quality and is therefore very undesirable, materials which have been made antistatic and do not display these phenomena are increasingly demanded for motor vehicle interiors.
Furthermore, low-emission materials are increasingly demanded for motor vehicle interiors so as to create a

pleasant interior atmosphere in the automobile and also to effectively suppress interior fogging of the windows by volatile constituents diffusing out of the plastic components. Low-fogging materials are thus increasingly required for motor vehicle interiors: some motor vehicle manufacturers have now already laid down upper limits for the fogging of interior materials. There are in principle two methods for measuring the fogging value: a reflecto-metric method and a gravimetric method. The gravimetric method is the more reliable and has now become established. It is described in the standard DIN 75201. The maximum alloweUsle upper limit for the fogging of interior lining materials of current German automobiles is at present If plastic parts, in particular those of polypropylene, are made antistatic, this is generally achieved by the addition of specific antistatic agents which migrate to the surface of the molding and there form a film of moisture by means of hydrophilic groups. For poly¬propylene and talc-reinforced polypropylene, glyceryl monostearate, glyceryl distearate and ethoxylated alkyl-amines are used for this purpose (see: Modern Plastics International, Nov. 1988, 86-92). The moisture increases the surface conductivity and electrostatic charging is avoided. Since the known antistatic additives have to be added in relatively high concentrations to reliadsly ensure the desired action, and since they themselves are of relatively low molecular weight and furthermore are located on the surface of the moldings, they contribute very greatly to the fogging. Thus, moldings containing an antistatic agent normally always have comparatively high fogging values.
It is thus an object of the present invention to provide particular antistatic agents for talc-reinforced poly¬propylene which, on the one hand, meet the particularly high requirements for motor vehicle interiors in respect of fogging and, on the other hand, effectively suppress

dust deposits resulting from electrostatic forces.
It has now surprisingly been found that this object is achieved according to the invention by an injection-molding composition based on a talc-reinforced propylene polymer containing an additive combination of glyceryl monostearate plus fatty acid dialkanolsunide in a mixing ratio in the range from 1:1 to 3:1 and a total amount of up to 1.5 % by weight, based on the weight of the propylene polymer.
For the purposes of the present invention, a talc-reinforced propylene polymer is a propylene homopolymer or block copolymer comprising up to 17 % by weight of ethylene vinits and having a talc content of up to 40 % by weight, based on the weight of the propylene polymer. However, it is also possible to use random copolymers or graft copolymers comprising propylene building blocks as main constituent or mixtures of polypropylene with other polymers compatible therewith, such as rubber-like copolymers. The addition of talc should prefereibly be in the range from 10 to 3 0 % by weight.
For the purposes of the present invention, lauric diethanoleunide or oleic diethanoleuaide should preferably be used as fatty acid dialkanolamide, with the preferred total amount of the additive combination of glyceryl monostearate plus fatty acid dialkanoleunide being in the range from 0.6 to 1.2 % by weight, based on the weight of propylene polymer.
In numerous tests, the injection-molding composition of the invention was found to be more effective in respect of electrostatic charging than the mixtures of glyceryl monostearate and ethoxylated alkyleunines known from the literature and, in addition, surprisingly gave lower fogging values.
The following exaunples are to clarify the invention for

those skilled in the art. In these examples, the influence of various antistatic agents on the reduction of electrostatic charging and fogging behavior was examined by preparing talc-reinforced PP compounds comprising a PP copolymer and different concentrations of various antistatic agents. Glyceryl monostearate, mixtures of glyceryl monostearate and glyceryl distearate, ethoxylated alkylaunines having different chain lengths and lauric diethanolamide were here used in different concentrations and mixing ratios. The propor¬tion of talc, the chemical composition of the copolymer, the impact modifier and the other additives such as processing stabilizers, antioxidants, light stabilizers and processing aids were not varied.
To exeunine the electrostatic charging and the soiling, stacking boxes were injection molded from the compounds under constant conditions, demolded by means of suction pick-ups and stored in a relatively dusty place where they were exposed to the prevailing environmental conditions. These conditions duplicate practical condi¬tions very well and simulate a production process for producing an injection-molded part, e.g. for motor vehicle applications. In the case of parts not containing an antistatic agent, the typical dust patterns appear on the surface of the molding after a few hours, but at the latest after a few days. These generally first appear at the point of contact of the suction pick-up, since the greatest charge separation occurs here. For comparison, the specific surface resistance of the moldings was also measured under constant conditions (in accordance with DIN lEC 93; VDE 0303 Part 30, on 1 son plates 8x8 cm, specific surface resistance = surface resistance x 10).
To examine the fogging behavior, 3 mm plates were injec¬tion molded under clean conditions and the fogging value was siibseguently determined gravimetrically in accordance with DIN 75201 at a temperature of 100"C over a period of 16 hours. In each case, a mean was determined from

4 measurements which were measured in two passes. The percentages given in the examples are in each case by weight.
It can be seen from Table 1 that in the case of talc-reinforced PP containing an antistatic agent alone, a good antistatic effect does not appear until relatively-high concentrations are reached (compounds 5 and 12). However, the fogging values here are very high (fogging values Surprisingly, in the case of mixtures of glyceryl mono¬stearate with lauric diethanolamide in a certain concen¬tration ratio, a very good antistatic effect with a very low tendency to soiling is obtained together with a simultaneously low fogging value (compoiind 11) . An unexpected synergistic effect is thus present here. This becomes particularly clear in the comparison of compound 11 with the compoiinds 4 and 12 in which the antistatic agents were in each case used alone in the seune total concentration of 0.7 %. The comparison with compounds 7 and 9 also makes it clear that lauric diethanolaunide is surprisingly a better synergist in respect of an anti-static effect and the fogging behavior than are the ethoxylated alkylamines used according to the prior art.
The advantage of the additive combination of the inven¬tion is thus that an effective antistatic action together with low electrostatic charging can be achieved at low use concentrations and a low long-term tendency to soiling is thus ensured. The undesireible fogging behavior is at the same time greatly reduced. As a result of the higher effectiveness, formulation costs can also be saved during manufacture.

The injection-molding compositions of the invention can be advantageously used for motor vehicle interior trim components such as coverings of A, B, C columns, dash¬boards, door linings, seat coverings, glove compartments and consoles, but equally well for household goods such as toaster housings, coffee machines, irons, electrical installation components or moldings for office furniture.
Accordingly, the present invention provides an injection-molding composition comprising a talcum-reinforced propylene polymer having talcum in an amount of 10 to 40% by weight, based on the weight of the propylene polymer, an additive combination of glyceryl monostearate plus fatty acid dialkanolamide in a mixing ratio in the range from 1:1 to 3:1 and a total amount of up to 1.5% by weight, based on the weight of the propylene polymer.

The injection-molding compositions of the invention can be advantageously used for motor vehicle interior trim components such as coverings of A, B, C columns, dash¬boards, door linings, seat coverings, glove compartments and consoles, but equally well for household goods such as toaster housings, coffee machines, irons, electrical installation components or moldings for office furniture.
The molding compositions of the invention can be processed using the normal processing conditions for polypropylene and reinforced polypropylene. The process¬ing temperatures are, depending on size and geometry of the molding, in the range from 240 to 280°C. The tool temperature is generally from 3 0 to 70°C.
Exeunple 1 (comparative example)
A mixture of 75 parts by weight (pbw) of a propylene block copolymer (7 % ethylene content, MFI 230/2.16 of 7.0 g/10 min) , 5 pbw of an EPM rubber (52 % propylene, 48 % ethylene, Mooney viscosity ML (1+4) 125°C of 80), 20 pbw of talc having a particle size distribution of 99 % Exeunple 2 (comparative example)
A mixture was prepared in a twin-screw extruder using a method similar to Exaunple 1, with the sole difference

that 0.7 pbw of glyceryl monostearate (purity 55 %, remainder glyceryl distearates and tristearates) was additionally added. The results are shown in Table 1.
Example 3 (comparative example)
A mixture was prepared as in Example 1. However, an amount of 0.5 pbw of glyceryl monostearate (purity 95 %, mp. 69°C) was additionally added. The results are shown in Table 1.
Example 4 (comparative exeunple)
A mixture was prepared as in Example 1. 0.7 pbw of glyceryl monostearate (purity 95 %, mp. 69C was addi¬tionally added. The results are shown in Tahle 1.
Exeunple 5 (comparative example)
A mixture was prepared as in Example 1. 1.0 pbw of glyceryl monostearate (purity 95 %, mp. 69'C) was addi¬tionally added. The results are shown in Table 1.
Example 6 (comparative example)
A mixture was prepared as in Exounple 1. 0.3 pbw of glyceryl monostearate (purity 95 %, mp. 69°C) and 0.15 pbw of alkyldiethanoleunine (mean chain length: 15 carbon atoms, solidification point: +2'C) were additionally added. The results are shown in Table 1.
Example 7 (comparative example)
A mixture was prepared as in Example 1. 0.5 pbw of glyceryl monostearate (purity 95 %, mp. 69°C) and 0.2 pbw of alkyldiethanoleunine (mean chain length: 15 carbon atoms, solidification point: +2'C) were additionally added. The results are shown in Table 1.

Example 8 (comparative example)
A mixture was prepared as In Example 1. 0.3 pbw of glyceryl monostearate (purity 95 %, mp. 69C) and 0.15 pbw of alkyldiethanolamine (mean chain length: 18 carbon atoms, solidification point: +60°C) were additionally added. The results are shown in Table 1.
Example 9 (comparative exeunple)
A mixture was prepared as in Exaunple 1. 0.5 pbw of glyceryl monostearate (purity 95 %, mp. GS'C) and 0.2 pbw of alkyldiethanoleunine (mean chain length: 18 carbon atoms, solidification point: +60°C} were additionally added. The results are shown in Table 1.
Example 10 (according to the invention)
A mixture was prepared as in Example 1. 0.3 pbw of glyceryl monostearate (purity 95 %, mp. 69"C) and 0.15 pbw of lauric diethanolaunide (melting point: aQ>out 45°C) were additionally added. The results are shown in Table 1.
Exeunple 11 (according to the invention)
A mixture was prepared as in Example 1. 0.5 pbw of glyceryl monostearate (purity 95 %, mp. 69°C) and 0.2 pbw of lauric diethanolamide (melting point: about 45°C) were additionally added. The results are shown in Table 1.
Example 12 (comparative example)
A mixture was prepared as in Example 1. 0.7 pbw of lauric diethanoleunide (melting point: about 45°C) was addition¬ally added. The results are shown in Table 1.





WE CLAIM:
1. An injection-molding composition comprising a talcum-reinforced propylene polymer having talcum in an amount of 10 to 40% by weight, based on the weight of the propylene polymer, an additive combination of glyceryl monostearate plus fatty acid dialkanolamide in a mixing ratio in the range from 1:1 to 3:1 and a total amount of up to 1.5% by weight, based on the weight of the propylene polymer.
2. The injection-molding composition as claimed in claim 1, wherein the propylene polymer is a propylene homopolymer or block copolymer comprising up to 17% by weight of ethylene units and having a talc content of up to 40% by weight, based on the weight of the propylene polymer, or a random copolymer or graft copolymer comprising propylene building blocks as main constituent or a mixture of polypropylene with other polymers compatible therewith, such as rubber-like copolymers.
3. The injection-molding composition as claimed in claim 2, wherein the propylene copolymer is a block copolymer comprising up to 17% by weight of ethylene units.
4. The injection-molding composition as claimed in claim 2, wherein the addition of talc is in the range from 10 to 30%) by weight, based on the weight of the propylene polymer.
5. The injection-molding composition as claimed in any of claims 1 to 4, wherein the composition contains lauric diethanolamide or oleic diethanolamide as fatty acid dialkanolamide.

6. The injection-molding composition as claimed in any of claims 1 to 5, wherein the total amount of the additive combination of glyceryl monostearate plus fatty acid dialkanolamide is in the range from 0.6 to 1.2% by weight, based on the weight of propylene polymer.
7. A method for the preparation of molded article such as moldings for automotive vehicle interior trim and household goods comprising the step of molding such articles by employing an injection molding composition as claimed in one of the claims 1 to 6.
8. An injection-molding composition comprising a talcum-reinforced propylene polymer substantially as herein described and exemplified.


Documents:

581-mas-1996 abstract.pdf

581-mas-1996 claims.pdf

581-mas-1996 correspondence others.pdf

581-mas-1996 correspondence po.pdf

581-mas-1996 description (complete).pdf

581-mas-1996 form-2.pdf

581-mas-1996 form-26.pdf

581-mas-1996 form-4.pdf

581-mas-1996 form-6.pdf

581-mas-1996 others.pdf

581-mas-1996 petition.pdf


Patent Number 193846
Indian Patent Application Number 581/MAS/1996
PG Journal Number 20/2006
Publication Date 19-May-2006
Grant Date 05-Dec-2005
Date of Filing 08-Apr-1996
Name of Patentee M/S. HOECHST AKTIENGESELLSCHAFT
Applicant Address D-65926 FRANKFURT AM MAIN,
Inventors:
# Inventor's Name Inventor's Address
1 DR. JURGEN ROHRMANN HAINPFAD 5, 65779 KELKHEIM,
PCT International Classification Number C08J5/16
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 195 13 986.0 1995-03-13 Germany