OA16649A - Moulding method. - Google Patents
Moulding method. Download PDFInfo
- Publication number
- OA16649A OA16649A OA1201300455 OA16649A OA 16649 A OA16649 A OA 16649A OA 1201300455 OA1201300455 OA 1201300455 OA 16649 A OA16649 A OA 16649A
- Authority
- OA
- OAPI
- Prior art keywords
- article
- polymeric composition
- daims
- degree
- blowing agent
- Prior art date
Links
- 238000000465 moulding Methods 0.000 title description 3
- 239000000203 mixture Substances 0.000 claims abstract description 12
- 239000004604 Blowing Agent Substances 0.000 claims description 4
- 238000007664 blowing Methods 0.000 claims description 4
- 239000000047 product Substances 0.000 claims description 4
- 238000001746 injection moulding Methods 0.000 claims description 3
- 239000012467 final product Substances 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims description 2
- 239000005977 Ethylene Substances 0.000 claims 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 claims 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 206010022114 Injury Diseases 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 241000251730 Chondrichthyes Species 0.000 description 1
- 241000238814 Orthoptera Species 0.000 description 1
- 235000019589 hardness Nutrition 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 230000001681 protective Effects 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
Abstract
The invention provides for a method of manufacturing a hollow article, which includes the step of introducing a polymeric composition that is settable into an article that has a shape-retaining property and at the same time a degree of flexibility which is yet insufficient to cause distortion of the article on the application of normal force. (fig. 1)
Description
MOULDING METHOD
TECHNICAL FIELD OF THE INVENTION
This invention relates to a method of moulding hollow articles and more specifically articles having a shell with an opening such as headgear, pots, and the like.
BACKGROUND ART
The invention is particularly suited to the manufacture of helmets which are generally manufactured by injection moulding using thermoplastic material in order to produce strong, missile-proof articles for the mining and other industries, for police and army duties, as well as domestîc and leisure activities in which case it is not only for protective purposes.
One of such activities is sport watching and, in particular cricket of the twenty-20 variety where sixes predominate in the play and which may cause injury to spectators. Such helmets are also used extensively for other sports such as rugby and one has only to watch TV live broadcasts to notice the large number of BULLS or SHARKS helmets at rugby games.
However, at rugby or soccer and other matches it not really necessary to hâve missile-proof properties- in fact, such helmets can be uncomfortable and it is one of the objects ofthe présent invention to provide a bel met that can be of conventional shape and configuration and yet far more comfortable for the wearer.
DISCLOSURE OF THE INVENTION
According to the invention a method of manufacturing a hollow article includes the step of introducîng a polymeric composition that is settable into an article that has a shaperetaining property and at the same time a degree of flexibility which is yet insufficient to cause distortion of the article on the application of normal force.
In a preferred form of the invention the method involves injection moulding and the polymeric composition is chosen according to its property of setting into the desired flexible product. The composition may ideally also include a blowing agent, which imparts lightness to the final product.
The preferred polymer ts ethyiene vinyl acetate (EVA), in ail its grades and shore hardnesses.
The distance between the inner and outer éléments of the mould is chosen having regard to the desired thickness of the article and, in the case of the use of a blowing agent the amount of composition used is predetermined according to the degree of expansion due to the blowing agent- or the desired degree of blowing required for the particular thickness.
It will be appreciated that the invention may be applied to the production of a number of articles such as flower or plant pots, kitchenware, omaments and many others.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is illustrated in the accompanying pictures, in which:
Figure 1 is a drawing of a mould as used in the method of manufacture; and
Figure 2 is a photograph of an example of a product produced using the method of manufacture.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the sketch a mould is depicted with an outer element 10 and an inner element 12 spaced apart by a predetermined distance 14.
The polymeric composition is introduced in the usual manner and, as discussed above, its volume is predetermined in relation to the density of the wall of the produced article and also taking into considération the degree of blowing expansion required.
A typical product of the invention is shown in figure 2. Despite having the appearance of a conventional helmet 20, it has a degree of ftexibility that imparts comfort. !n addition, the homs 22 are sufficiently flexible and déformable to prevent injury upon engagement with another person.
Claims (8)
- CLAJMS:1. A method of manufaduring a hollow article characterised in that the method includes the step of introducing a settable polymeric composition into an article that has a shape-retaining property and at the same time a degree of flexibility which is yet insufficient to cause distortion of the article on the application of normal force.
- 2. The method of daim 1 characterised tn that the polymeric composition is introduced by injection moulding.
- 3. The method of either of daims 1 or 2 characterised in that the polymeric composition is chosen according to its property of setting into the desired flexible product.
- 4. The method of daim 3 characterised in that the composition ideally includes a blowing agent, which imparts lightness to the final product.
- 5. The method of any of daims 1 to 4 characterised in that the polymer is ethylene vinyi acetate (EVA), in ail its grades and shore-hardnesses.
- 6. The method of any of daims 1 to 5 characterised in that the distance between the inner and outer éléments of the mould is chosen having regard to the desired thickness of the article.
- 7. The method of any of daims 4 to 6 characterised in that the amount of polymeric composition used is predetermined according to the degree of expansion due to the blowing agent.
- 8. The method of any of daims 4 to 6 characterised in that the amount of polymeric composition used is predetermined according to the desired degree of blowing required for the particular thickness.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA2011/03609 | 2011-05-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| OA16649A true OA16649A (en) | 2015-12-01 |
Family
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