Process for preparing flowable amorphous poly-alpha olefin adhesive pellets

Patent metadata

Field	Value
Publication number	US-9364985-B2
Application number	US-201313803814-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	May 24, 2012
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

The present invention relates to a process for producing free-flowing, agglomeration resistant amorphous poly-alpha-olefin based adhesive pellets. The process includes (a) extruding the adhesive through an orifice of a die plate immersed in a cooling fluid; (b) cutting the adhesive into a plurality of pellets in the cooling fluid; (c) solidifying the pellets at a temperature range of about 25° C. to about 40° C. for at least 30 minutes; and (d) separating the pellets from the recrystallization fluid and drying the pellets. The pellets harden at least three folds faster than conventionally formed pellets.

First claim

We claim:

1. A process for forming a plurality of hot melt adhesive pellets comprising the steps of:
a) extruding an adhesive through an orifice of a die plate immersed in a cooling fluid, which has a temperature T1;
b) cutting the adhesive into a plurality of pellets in the cooling fluid;
c) solidifying the pellets in a recrystallization fluid at temperature T2 for at least 30 minutes and up to 24 hours;
d) separating the pellets from the recrystallization fluid and drying the pellets;
wherein the T1 is less than about 45° F. and the T2 is higher than T1 by at least 30° F.
wherein the adhesive comprises an amorphous poly-alpha-olefin polymer having a cold crystallization temperature;
wherein the adhesive has a needle penetration number of (i) 8 to 50 dmm after 1 hour conditioning at 77° F., (ii) 10 to 45 dmm after 4 hour conditioning at 77° F., and (iii) 10 to 40 dmm after 24 hour conditioning at 77° F.; and
wherein the pellets have an average percent deformation, (d 0 -d 1 )/d 0 ×100%, less than 40%, where d 0 is an initial diameter and d 1 is a diameter measured after applying a weight of 70 g for one minute.

2. The process of claim 1 wherein the T2 has a temperature range of about 77° F. to about 104° F.

3. The process of claim 2 wherein the T2 has a temperature range of about 86° F. to about 95° F.

4. The process of claim 1 wherein the pellets are held in the recrystallization fluid for at least about 60 minutes up to about 180 minutes.

5. The process of claim 4 wherein the pellets are held in the recrystallization fluid for at least about 100 minutes up to about 150 minutes.

6. The process of claim 1 wherein the amorphous alpha-olefin polymer comprises a comonomer of ethylene, propylene, butene, pentene, hexane, heptene, octane, nonene, decene, undecene, dodecene, and mixtures thereof.

7. The process of claim 6 wherein the amorphous alpha-olefin polymer comprises a comonomer of propylene and butene.

8. The process of claim 1 wherein the adhesive has a needle penetration number of (i) 15 to 40 dmm after 1 hour conditioning at 77° F., (ii) 15 to 40 dmm after 4 hour conditioning at 77° F., and (iii) 10 to 30 dmm after 24 hour conditioning at 77° F.

9. The process of claim 8 wherein the adhesive has a cold crystallization temperature of about 77° F. to about 105° F.

10. The process of claim 9 wherein the adhesive has a cold crystallization temperature of about 82° F. to about 104° F.

Assignees

• Henkel IP & Holding GmbH

Inventors

• Desai Darshak
• Hu Yuhong
• Gaspar Ken
• Hantwerker Ed

Classifications

• B29K2023/18

  Polymers of hydrocarbons having four or more carbon atoms, e.g. polymers of butylene, e.g. PB, i.e. polybutylene · CPC title

• B29C48/0022

  combined with cutting · CPC title

• B29C71/0063

  for changing crystallisation · CPC title

• B29C2948/92714

  Degree of crosslinking, solidification, crystallinity or homogeneity · CPC title

• B29C48/919

  using a bath, e.g. extruding into an open bath to coagulate or cool the material · CPC title