Apparatus and method for making molded foam articles

• US 20030085483A1
• Filed: 11/05/2001
• Published: 05/08/2003
• Est. Priority Date: 11/05/2001
• Status: Abandoned Application

• Current Assignee: Caco Pacific Corporation
• Original Assignee: Caco Pacific Corporation
• Inventors: Kroeger, Charles
• Application Number:
  US10/011,950
• Publication Number:
  US 20030085483A1
• Time in Patent Office: Days
• US Class Current: 264/51
• CPC Class Codes: B29C 44/424 Details of machines
• CPC Class Codes: B29C 44/588 with means for venting, e.g. releasing foaming gas
• CPC Class Codes: B29C 45/125 using a material distributing system

Abstract

A mold apparatus useful for making molded foam articles has a pair of independently operated mold modules, both fed by a single hot melt injection unit. In a preferred, but not necessary, embodiment, each of the opposed mold portions of each mold module is retained in its respective closed position by a simple mechanical latch. In such a preferred embodiment, it is further preferred that, in the closed position, the two mold portions of each mold module are separated by a narrow air gap to allow air to escape from each mold module during operation.

Claims

1. A mold apparatus useful for making molded foam articles, the mold apparatus comprising:

(a) a first mold module having a plurality of mold cavities, the first mold module comprising a first portion and a second portion, the first portion and the second portion being moveable with respect to one another between an open position and a closed position;

(b) a second mold module having a plurality of mold cavities, the second mold module comprising a first portion and a second portion, the first portion of the second mold module and the second portion of the second mold module being moveable with respect to one another between an open position and a closed position; and

(c) a hot melt injection unit for heating and delivering one or more components of a molded foam article feedstock, the hot melt injection unit being capable of alternatively directing feedstock to the first mold module or to the second mold module.

2. The mold apparatus of claim 1 wherein the first mold module and the second mold module are both retained within their respective closed positions by a mechanical latch.

3. The mold apparatus of claim 1 wherein, (i) when the first mold module is disposed within the closed position, an air gap is provided between the first portion of the first mold module and the second portion of the first mold module, the air gap being between 0.005 inches and 0.020 inches, and (ii) when the second mold module is disposed within the closed position, an air gap is provided between the first portion of the second mold module and the second portion of the second mold module, the air gap within the second mold module being between 0.005 inches and 0.020 inches.

4. The mold apparatus of claim 1 wherein, (i) when the first mold module is disposed within the closed position, an air gap is provided between the first portion of the first mold module and the second portion of the first mold module, the air gap being between 0.005 inches and 0.020 inches, and (ii) when the second mold module is disposed within the closed position, an air gap is provided between the first portion of the second mold module and the second portion of the second mold module, the air gap within the second mold module being between 0.005 inches and 0.020 inches, and wherein both the first mold module and the second mold module are retained within their respective closed positions by a mechanical latch.

5. The mold apparatus of claim 4 wherein each mechanical latch is adjustable such that the air gaps provided when the first mold module and the second mold module are disposed within their respective closed positions are both adjustable.

6. The mold apparatus of claim 1 wherein the hot melt injection unit comprises an upstream end and a downstream end, the downstream end having a rotary valve capable of alternatively directing feedstock to the first mold module or to the second mold module.

7. The mold apparatus of claim 1 wherein the hot melt injection unit comprises an upstream end and a downstream end, the downstream end having a three-way valve capable of alternatively directing feedstock to the first mold module or to the second mold module.

8. The mold apparatus of claim 1 wherein the hot melt injection unit comprises an upstream end and a downstream end, the downstream end having a plurality of valves capable of alternatively directing feedstock to the first mold module or to the second mold module.

9. The mold apparatus of claim 1 wherein the first portion of each mold module is stationary and the second portion of each mold module is moveable and wherein the hot melt injection unit is capable of alternatively directing feedstock to the first portion of the first mold module or to the first portion of the second mold module.

10. A mold apparatus useful for making molded foam articles, the mold apparatus comprising:

(a) a first mold module having a plurality of mold cavities, the first mold module comprising a stationary first portion and a moveable second portion, the first portion and the second portion being moveable with respect to one another between an open position and a closed position;

(b) a second mold module having a plurality of mold cavities, the second mold module comprising a stationary first portion and a moveable second portion, the first portion and the second portion being moveable with respect to one another between an open position and a closed position;

(c) a hot melt injection unit for heating and delivering one or more components of a molded foam article feedstock, the hot melt injection unit comprising an upstream end and a downstream end, the downstream end having a rotary valve capable of alternatively directing feedstock to the first portion of the first mold module or to first portion of the second mold module;

wherein, (i) when the first mold module is disposed within the closed position, an air gap is provided between the first portion of the first mold module and the second portion of the first mold module, the air gap being between 0.005 inches and 0.020 inches, and (ii) when the second mold module is disposed within the closed position, an air gap is provided between the first portion of the second mold module and the second portion of the second mold module, the air gap within the second mold module being between 0.005 inches and 0.020 inches.

11. The mold apparatus of claim 10 wherein both the first mold module and the second mold module are retained within their respective closed positions by a mechanical latch.

12. The mold apparatus of claim 11 wherein each mechanical latch is adjustable, such that the air gaps provided when the first mold module and the second mold module are disposed within their respective closed positions are both adjustable.

13. A mold apparatus useful for making molded foam articles, the mold apparatus having a plurality of mold cavities and further comprising:

(a) a first mold portion and a second mold portion, the first mold portion and the second mold portion being moveable with respect to one another between an open position and a closed position; and

(b) a hot melt injection unit for heating and delivering one or more components of a molded foam article feedstock, the hot melt injection unit being capable of alternatively directing feedstock to the first mold module or to the second mold module;

wherein, when the first mold portion and the second mold portion are disposed within the closed position, an air gap is provided between the first mold portion and the second mold portion, the air gap being between 0.005 inches and 0.020 inches.

14. The apparatus of claim 13 wherein the first mold portion and the second mold portion are retained within the closed position by a mechanical latch.

15. The mold apparatus of claim 14 wherein the mechanical latch is adjustable such that the air gap provided when the first mold portion and the second mold portion are disposed within the closed position is adjustable.

16. A method for making molded foam articles comprising the steps of:

(a) providing a mold apparatus comprising;

(i) a first mold module having a plurality of mold cavities, the first mold module comprising a first portion and a second portion, the first portion and the second portion being moveable with respect to one another between an open position and a closed position;

(ii) a second mold module having a plurality of mold cavities, the second mold module comprising a first portion and a second portion, the first portion and the second portion being moveable with respect to one another between an open position and a closed position; and

(iii) a hot melt injection unit for mixing, heating and delivering one or more components of a molded foam article feedstock, the hot melt injection unit being capable of alternatively directing feedstock to the first mold module or to the second mold module;

(b) combining molded foam article starting resin and a blowing agent to form a molded foam article feedstock;

(c) heating the molded foam article feedstock;

(d) delivering some of the molded foam article feedstock with the hot melt injection unit to the first mold module;

(e) molding molded foam article feedstock in the first mold module while heating other of the molded foam article feedstock in the hot melt injection unit;

(f) delivering some of the molded foam article feedstock with the hot melt injection unit to the second mold module and removing molded foam articles from the first mold module;

(g) molding molded foam article feedstock in the second mold module while heating other of the molded foam article feedstock in the hot melt injection unit;

(h) delivering some of the molded foam article feedstock with the hot melt injection unit to the first mold module and removing molded foam articles from the second mold module; and

(i) repeating steps (e)-(h) at least ten times.

17. The method of claim 16 wherein the molded foam article starting resin comprises a blend of polypropylene and thermoplastic elastomer.

18. The method of claim 16 wherein the molding of molded foam article feed stock in the first mold module in step (e) is carried out while maintaining an air gap between the first portion of the first mold module and the second portion of the first mold module, such air gap being between 0.005 inches and 0.020 inches, and wherein the molding of molded foam article feed stock in the second mold module in step (g) is carried out while maintaining an air gap between the first portion of the second mold module and the second portion of the second mold module, such air gap between the first portion of the second mold module and the second portion of the second mold module being between 0.005 inches and 0.020 inches.

19. The method of claim 18 wherein, during the molding of molded foam article feed stock within the first mold module in step (e), the air gap between the first portion of the first mold module and the second portion of the first mold module is maintained by a mechanical latch and wherein during the molding of molded foam article feed stock in the second mold module in step (g), the air gap between the first portion of the second mold module and the second portion of the second mold module is maintained by a mechanical latch.

20. The method of claim 19 wherein, prior to the molding of molded foam article feed stock in the first mold module in step (e), the air gap between the first portion of the first mold module and the second portion the first mold module is adjusted.

21. A method for making molded foam articles comprising the steps of:

(a) providing a mold apparatus comprising;

(i) a first mold portion and a second mold portion, the first mold portion and the second mold portion being moveable with respect to one another between an open position and a closed position; and

(ii) a hot melt injection unit for heating and delivering one or more components of a molded foam article feedstock, the hot melt injection unit being capable of alternatively directing feedstock to the first mold module or to the second mold module;

wherein, when the first mold portion and the second mold portion are disposed within the closed position, an air gap is provided between the first mold portion and the second mold portion, the air gap being between 0.005 inches and 0.020 inches;

(b) combining molded foam article starting resin and a blowing agent to form a molded foam article feedstock;

(c) heating the molded foam article feedstock;

(d) delivering some of the molded foam article feedstock with the hot melt injection unit to the mold cavities; and

(e) molding molded foam article feedstock within the mold cavities while maintaining the first mold portion and the second mold portion disposed in the closed position with an air gap between the first mold portion and the second mold portion of 0.005 inches and 0.020 inches.

22. The method of claim 21 wherein, prior to the molding of foam article feed stock in step (e), the air gap between the first mold portion and the second mold portion when the first mold portion and the second mold portion are disposed within the closed position is adjusted.