JPS615998A - Eraser having thermoplastic substance and manufacture thereof - 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 Field of Industrial Application The present invention relates to a thermoplastic material, the thermoplastic material being a P.lambda. It's about Shiko.

Prior Art DE 30 43 941 discloses, inter alia, such polymers containing slightly crystallizable polyolefin graft copolymer elastomers prepared by polymerization of ethylene and/or (α-)olefins. An eraser is listed. This elastomer is mixed with factice, fillers and pigments and processed into erasers.

In addition, the above mixture may be added in particular to a rubber based on an ethylene/propylene terpolymer, optionally with
An ethylene/propylene/diene copolymer may also be added.

However, erasers of this type are extremely chemically unstable due to the factice, which is an essential component in this case. Historically, the eraser in this case does not contain a softening agent, so the consistency of the base ablation cannot be adjusted arbitrarily. As a result, it is not possible to process these materials using any conventional eraser manufacturing equipment. Moreover, in this case the hardness of the finished eraser can only be varied within relatively narrow limits. Therefore, it is extremely aging unstable and has good JC wear characteristics7.
One means of solving the problem is to provide an eraser which is capable of variable hardness adjustment within a wide range and which can be manufactured on any conventional manufacturing equipment. This is not particularly easy to solve due to the characteristics described in the independent a^ requirement. Special aspects and details and advantages θ, is fat￥f)i? + A < range as described in Section 2 below.

Function Completely crosslinks and embeds the rubber.
I: Based on plastic olefin <:1 Synthetic component: j,
In order to manufacture erasers, it has been proven that (・τ extremely suitable <1.
+9i desired no) special? iI'v and can be manufactured more easily and inexpensively.

The synthetic components used in the invention and their preparation have been known per se for several years, for example from US Pat. No. 4,130,535. However, in the specification VC[H4'/J<
Since this mixture has been proposed especially for producing hard vulcanized products with thermoplastic properties, from this disclosure it is immediately possible to use it to produce hard, vulcanized products that are always flexible and heat-resistant in their own right. It is completely inconceivable that an eraser, which need not be plastic, would exhibit particularly good properties.

The hot white plastic melefin polymerizes in situ to form 71 ethylene-propylene-monoolefins (abbreviated as EPDM).
It has proved particularly advantageous if the polyzolopylene has the same ethylene, propylene and conjugated diene (. The unconjugated diene may advantageously be an enarytenorbornene, while the rubber is crosslinked with sulfur and has a degree of crosslinking of 7×10 mol/ It should have a particle size of 05 to 2 μm, preferably lμIn.

In addition, other additives such as styrene//bumenoene block comonomer (SBS), styrene/isoprene rubber (
SIS), ethylene/zolopyrene co- and/or terpolymer (ppM), VolJ vinyl chloride (PVC),
rt
d! i (carbonate), zinc sulfide, red sea bream oxide,
Butano 1, barite, pumice powder, glass powder, glass powder and/
y.

is used as a factice or as a softening agent.
Polybutanoene, polyalgylbene/naphdenoid yarn 71b-7 clay 1 or other Nisdel, and optionally organic pigments as dyes 1). good.

This defense: C-cross eraser can be produced by the following method. 1. In a first separate production step, the synthetic component is prepared by first completely crosslinking the rubber and then embedding it in the olefin and copolymerizing it therewith. In this case, the polymerization includes one and even two polymerizations between the rubber and the olefin, respectively themselves.

The resulting synthetic component is therefore a co'811 composite consisting of a polyolefin and a fully polymerized, fully crosslinked rubber. This production process can be carried out externally, ie independently of the actual eraser production.

Optionally, this combination can also be manufactured by a special manufacturer and provided as a commercial product.

The original eraser is then produced in a manner known per se. In this case, the previously produced copolymer is used as a synthetic component and mixed with other components of the entire composition to form a homogeneous (dispersed) total mixture.

This entire mixture is then passed through an extruder, - an injection molding machine, in a conventional manner.
It is then plasticized and completely or partially formed (and optionally cut or formed to the desired thickness) using a press or other manufacturing equipment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the illustrated embodiments. In this case, description 5 is 1% by weight.

Example 1 (composition range example) Synthetic components (polyolefin and polymerized L, co-13 composite consisting of fully crosslinked rubber) 5-50% filler (
Calcium carbonate or other) 30-85% factice 0-30% its additives, especially other additives + iJ plastic silastics, e.g. SBS, SIS, PV
C Others 0-30% Other additives, such as softeners, stabilizers, dyes or others ○-50% each;
) depends on the user's needs and is primarily determined by the desired elasticity, mechanical strength, stiffness, hardness, abrasion, texture and other requirements for the final product or eraser.

Example 2 (Production Example 1) 20% synthetic ingredients, 40% chalk and 40% glass powder were mixed in a Henschelmischer mixer.
Mix for about 2 minutes. This mixture is then heated to 180-230°C in a counter-rotating double screw extruder.
The strands are plasticized and optionally formed into shaped strands, which are cooled, for example in a water bath, and subsequently cut into the customary sizes for erasers.

Example 3 (Production Example 2) 16% of the synthetic components, 8% of styrene/butadiene block copolymer (SBS), 13% of polyalkylbenzene and 63% of chalk were mixed in a Heinzmisc mixer (Heinzmisc).
(her) Mix with a high-speed stirrer to generate frictional heat. At about 110°C, melting of the material occurs. This material is cooled and granulated by controlling the temperature to 35° C. with a cooling mixture and pulverizing it. The granules are shaped into the desired eraser shape in an injection molding machine and optionally cooled after demolding.

Example beef (Production example 3) Synthetic ingredients 6%, SBS 8%, Polyalkylbe/Zen 1
3.5%, chalk 635% and factice 9% are heated to approx. 130° C. in a Heinz mixer and are then dissolved.

After cooling, the K-let is plasticized in an extruder at temperatures of 100 DEG to 160 DEG C. and extruded into strands, cooled, cut and optionally barreled.

Other mixing examples are listed in the table below.

The synthetic acid used and proposed in the present invention simultaneously forms a thermoplastic and acts as a binder, filler or other mixed component in the eraser mixture.

Claims (1)

[Scope of Claims] 1. An eraser containing a thermoplastic material, in which the thermoplastic material is a polyolefin copolymer, in which the synthetic component is a thermoplastic polyolefin, and the polyolefin is polymerized and completely crosslinked rubber is embedded. An eraser containing a thermoplastic substance, characterized in that it contains a thermoplastic substance. 2. Ethylene in which thermoplastic olefin is polymerized in situ/
Eraser according to claim 1, which is polypropylene with propylene/diene/monoolefin (EPDM). 3. The eraser according to claim 1 or 2, wherein the rubber consists of ethylene, propylene and a small amount of unconjugated diene. 4. The eraser according to claim 3, wherein the unconjugated diene is ethylidene-norbornene. 5. The eraser according to any one of claims 1 to 4, wherein the rubber is crosslinked with a sulfur crosslinking system. 6. The eraser according to claim 5, wherein the degree of crosslinking of the rubber is greater than 7×10^-^5 mol/l. 7. The eraser according to any one of claims 1 to 6, wherein the rubber has a particle size of 0.5 to 2 μm. 8. Other additives include styrene/butadiene block copolymers, styrene/isoprene rubber, ethylene/propylene co- and/or terpolymers, polyvinyl chloride, ethylene ethyl acrylate, atactic propylene and/or ethylene vinyl acetate. The eraser according to any one of claims 1 to 7, which contains: 9. The eraser according to any one of claims 1 to 8, which contains polybutadiene, polyalkylbenzene, paraffinic or naphthenic oil, and/or phthalate or other ester as a softening agent. 10, calcium carbonate, zinc sulfide, magnesium oxide,
The eraser according to any one of claims 1 to 9, which contains barite, pumice powder, glass powder, and/or phactis. 11. The eraser according to any one of claims 1 to 10, which contains an inorganic or organic pigment as a dye. 12. Synthetic components 5-50% by weight Fillers 30-85% by weight Factis 0-30% by weight Other additives 0-30% by weight Softeners and optionally stabilizers and/or fillers 0-30 parts 12. An eraser according to any one of claims 1 to 11, which is made of a material comprising: 13. A method for producing an eraser having a thermoplastic material, wherein the thermoplastic material is a polyolefin copolymer,
1. A process for producing an eraser containing a thermoplastic material, characterized in that the embedding of rubber in the olefin is carried out by polymerization, in which case the olefin and the rubber are simultaneously polymerized, each on their own and with each other. 14. The thermoplastic material is a polyolefin copolymer,
In the process of producing erasers with thermoplastics, synthetic components are first produced by polymerization of thermoplastic olefins and embedded, fully crosslinked rubber, and these components are combined with other components of the total composition and in a homogeneous total composition. A process for producing erasers with thermoplastics, characterized in that the mixture is mixed until a mixture is formed, and then plasticization and shaping are carried out in an extruder, injection molding machine, plate press or other equipment.