Physically Cross-linked Polyethylene Foam "SlimAce"

1.

INTRODUCTION

2.

Cross-linked polyethylene foams commercially available
can be classified into two types according to their production method: chemical cross-linking and physical crosslinking. Furukawa Electric produces a chemically crosslinked polyethylene foam by the trade name of "FoamAce"
since the company began the production for the first timein the world. While the foam of each type has its own
advantages thus finding suitable applications, Furukawa
Electric has recently developed a physically cross-linked
polyethylene foam named "SlimAce" in an effort toincrease its domestic market share as well as to improve
the properties of FoamAce. Now we can produce twotypes of cross-linked polyethylene foam, making this ourstrong point.

23SlimAce

Expansion ratio

4FoamAce

58FEATURES OF SLIMACE

Figure 1 shows the production range of FoamAce andSlimAce represented by the expansion ratio and thickness. FoamAce can produce thick products having a maximum thickness of 15 mm taking advantage of chemical
cross-linking, but the minimum thicknesses are 3 mm and2 mm for the high-expansion and low-expansion products,respectively. In contrast, SlimAce can produce thin foams
such as 2 mm thick products for 30 times expansion ratio,
1 mm for 10 times and 0.5 mm for 5 times, variety ofwhich allowing development of new products. In the production range where they overlap with each other, they
permit diversification of products' properties.
One of the typical features of SlimAce is miniaturizationof its cell structure. As can be seen in the magnified viewof cells shown in Figure 2, cells near the surface areminiaturized improving surface smoothness as well assurface appearance. At the same time, the cell membraneand skin layer become thin, decreasing the stiffness ofentire foam body and increasing the flexibility. Thus
SlimAce improves in appearance, texture and soft feelingcompared with FoamAce.

10New region

12Overlapping
region1520

3.

PROPERTIES OF SLIMACE

30
400.5 0.8 1.0 1.5 2.034568

10121520Foam thickness (mm)Figure 1

Figure 2

Production range of SlimAce and FoamAce.

Cell structure of SlimAce and FoamAce (150 magnification) Left: SlimAce Right: FoamAce

Table 1 shows the physical properties of SlimAce products. We have developed five types of standard grade: R-,K-, Z-, I- and J-grade as well as three types of special
grade: flame retardant P-grade using halogen-free flame
retarding agents, semiconductive D-grade and antistatic
C-grade. Among these, the Z-, I- and J-grade are intended
for property diversification and entry to new markets
together with the R- and K-grade for property improvements in the existing market whereby replacing FoamAce.
Standard typeR-grade: Standard grade (Fine cell structure andsmooth surface)
K-grade: Soft gradeZ-grade: Thin, high-strength grade
I-grade: Thin, high-strength, soft grade
J-grade: Thin, high-elasticity grade
Special typeP-grade: Flame retardant grade (Equivalent to UL94
HBF)1

Table 1

Physical properties of SlimAce products.

GradeR

Z(Standard)(High strength)

I

J(High strength, flexibility) (High elasticity)

Item

Unit

Expansion ratio

times

Thicknessmm321111

1

Densitykg/m3

67339067906790

MD

1,2104401,790

1,470

1,700

1,240

1,560

TD

580

230

850

580

980

650

930

MD

271349

34

52

38

47

TD

46

21

68

54

54

50

45

MD

210

190

220

170

420

320

560

TD

210

150

220

230

420

290

500

39

22

37

32

34

29

32

MD

-2.2

-1.5

-2.5

-3.1

-3.3

-1.4

-3.4

TD

-0.9

-0.9

+0.5

+0.2

-0.3

-0.6

-0.4

0.039

0.032

0.037

0.035

0.038

0.035

0.039

Tensile strength

Tear strength

Elongation

kPa

N/cm

1530

1015

1015

10%

Compression strength 25%

kPa

Dimensional change
70°C ✕ 22 hr%Heat conductivity at 25°C

W/m . K

Test methods are in compliance with JIS K 6767-1995

a) Flooring materialb) Substrate for adhesive tapeFigure 3

Applications of SlimAce.

D-grade: Semiconductive grade (Volume resistivity:107Ω or more)
C-grade: Antistatic grade (Surface resistivity: 1013Ω
or more)4.

APPLICATIONS OF SLIMACE

SlimAce has a broad array of applications including architectural material for floor and wall (Figure 3a), thermoinsulating and waterproof sheet for roofs, cushioning andpackaging material, various gaskets, substrate for adhesive tapes (Figure 3b), airtight component for houses(Figure 3c) in addition to general merchandize taking
advantage of its smooth surface.
In the area of flooring material, SlimAce is laminatedwith other surface layers made of PVC or olefins, to be
used as a sound-absorbing and cushioning material. The
success of the products has been achieved by the ease oflamination due to the upgraded surface smoothness
together with the improved flexibility.

2c) Airtight feedthroughIn the case of tape material, SlimAce of small thickness
is used as a substrate material to improve the adhesive
performance of tapes by pressing effects, through theadvantageous use of its high cushioning property, surface
smoothness and high precision in thickness.
In the field of housing material, SlimAce is used at
feedthroughs of highly airtight and thermo-insulating housings that are promoted under the Law for Promotion ofEffective Use of Resources. Bonded or molded SlimAce
products are used to fill the clearance between the walland the penetrating pipes such as water supply. SlimAce
is suitable for such uses because of its low transmission
coefficient for water vapor in addition to its softness.

5.

IN CONCLUSION

We have been successful in establishing two production
systems for different types of polyethylene foams, thereby
taking an advantageous business position over our competitors. Now we can make a proper selection from ourFurukawa Review, No. 22

2002products to meet the customers' requirements. We hope
we will be able to achieve customers satisfaction thus
finding an opportunity for developing new products.
For more information, please contact:
Sales Unit, Foam Products Department, Industrial
Products Division
TEL: +81-3-3286-3461
FAX: +81-3-3286-3472

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