Claims
- 1. A filled polymer, the filler comprising ultrafine natural calcium carbonate having an average statistical particle diameter of from 0.5 to 0.7 .mu. and a maximum diameter of from 3 to 4 .mu..
- 2. A filled polymer according to claim 1, wherein the polymer comprises rubber, a polyvinyl chloride-based foam, hard polyvinyl chloride or a polyvinyl chloride coating.
- 3. A filled polymer according to claim 1, wherein the filler is chalk produced from coccolith shells.
- 4. A filled polymer according to claim 1, wherein the filler is crystalline calcite.
- 5. A filled polymer according to claim 2 wherein the carbonate is chalk from coccolith shells.
- 6. A filled polymer according to claim 2 wherein the carbonate is crystalline calcite.
- 7. The filler polymer of claim 1 wherein the polymer comprises polychloroprene.
- 8. The filler polymer of claim 1 which is a polyvinyl chloride-based foam.
Priority Claims (2)
| Number |
Date |
Country |
Kind |
| 2309516 |
Feb 1973 |
DT |
|
| 2251099 |
Oct 1972 |
DT |
|
Parent Case Info
This is a continuation, of application Ser. No. 401,497, filed Sept. 27, 1973, and now abandoned.
German Pat. application P 22 51 099.2 and corresponding U.S. Pat. application Ser. No. 401,487 filed Sept. 27, 1973, now U.S. Pat. No. 3,904,130, relate to a mill for grinding minerals which are used as pigments or fillers, said mill being characterised in that the grinding elements consist of 30 to 70% by weight of zirconium oxide, 0.1 to 5% by weight of aluminium oxide and 5 to 20% by weight of silicon oxide.
This mill enables ultrafine minerals to be prepared. For example, chalk from coccolith shells can be ground ultrafine.
The use of natural calcium carbonate as filler in natural and synthetic polymers is already known.
Natural calcium carbonates have been used for a long time in the rubber industry where they are predominantly used as inexpensive fillers to give "body" to the mixtures and to reduce the cost price thereof. Furthermore, natural calcium carbonates are also used in chemical foams based on PVC, in hard PVC and in coating PVC.
Since the finest natural calcium carbonates hitherto known have an average statistical particle diameter of 2 to 4 .mu. and a maximum of 10 to 20 .mu., their practical usefulness is restricted; in some fields natural calcium carbonates are virtually not used at all.
The use of natural calcium carbonate as filler in natural and synthetic polymers has the main disadvantage that the static and, above all, the dynamic and physical properties of the products are impaired. These fillers are therefore also called "degrading fillers".
In order to obviate these disadvantages, synthetic calcium carbonates or other minerals have already been used, which were prepared by precpitation or other suitable processes. These fillers have mainly the disadvantage of being usable only for special purposes because of their comparatively complicated production, and hence not being usable at all in rubber, foams, hard PVC and coating PVC, and of giving rise to a very high comsumption of binding agent because of their needle-shaped structure.
Calcium carbonates of various degrees of fineness and different origin have been tested in extensive series of experiments over many years for their usability as fillers in natural and synthetic polymers. In further developing the invention of the main patent, German Patent Specification . . . (Patent application P 22 51 099.2) it has now been found that, surprisingly, ultrafine natural calcium carbonates with an average statistical particle diameter of 0.5 to 0.7 .mu. and a maximum of 3 to 4 .mu. can be used as fillers in natural and synthetic polymers.
Chalks from coccolith shells or crystalline calcite are primarily suitable as calcium carbonates.
The ultrafine natural calcium carbonates of the invention are preferably suitable as fillers in rubber, chemical foams based on PVC, in hard PVC and coating PVC.
The following comparative tests show the advantage of using the calcium carbonates of the invention in the rubber industry:
US Referenced Citations (3)
| Number |
Name |
Date |
Kind |
|
3268388 |
Bauman et al. |
Aug 1966 |
|
|
3373134 |
Yasui et al. |
Mar 1968 |
|
|
3443890 |
Sisson et al. |
May 1969 |
|
Non-Patent Literature Citations (2)
| Entry |
| Kraus-Reinforcement of Elastomers (Interscience) (N.Y.) (1965), pp. 187-188. |
| Rubber World-Materials & Compounding Ingredients for Rubber (Bill Publications) (N.Y.) (1968), pp. 280 & 294. |
Continuations (1)
|
Number |
Date |
Country |
| Parent |
401497 |
Sep 1973 |
|
Patent Grant
3959192
