U.S. patent application number 14/437807 was filed with the patent office on 2015-10-15 for bedding product comprising a foamed latex layer, slab of such foamed latex layer for cutting a bedding product therefrom and method of manufacturing thereof.
The applicant listed for this patent is Latexco N.V.. Invention is credited to Ruben De Gryse, Henk Demets.
Application Number | 20150289668 14/437807 |
Document ID | / |
Family ID | 47115476 |
Filed Date | 2015-10-15 |
United States Patent
Application |
20150289668 |
Kind Code |
A1 |
Demets; Henk ; et
al. |
October 15, 2015 |
Bedding Product Comprising a Foamed Latex Layer, Slab of Such
Foamed Latex Layer for Cutting a Bedding Product Therefrom and
Method of Manufacturing Thereof
Abstract
A method for producing a bedding product is disclosed which has
at least a foamed latex layer. The method includes pouring liquid
latex foam on a conveyor belt. The liquid latex foam is vulcanized
in a vulcanization station to obtain a vulcanized latex foam slab.
The vulcanized latex foam slab is cut to a desired length and/or
width. Electromagnetic waves with a frequency ranging between 1 and
50 Mhz are used for at least partially vulcanizing the liquid latex
foam.
Inventors: |
Demets; Henk; (Tielt,
BE) ; De Gryse; Ruben; (Tielt, BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Latexco N.V. |
Tielt |
|
BE |
|
|
Family ID: |
47115476 |
Appl. No.: |
14/437807 |
Filed: |
May 13, 2013 |
PCT Filed: |
May 13, 2013 |
PCT NO: |
PCT/EP2013/059822 |
371 Date: |
April 22, 2015 |
Current U.S.
Class: |
5/691 ; 264/425;
425/174; 428/220; 5/690 |
Current CPC
Class: |
B29C 35/0805 20130101;
B29C 2035/0861 20130101; B29L 2031/751 20130101; B29C 35/049
20130101; B29K 2105/0064 20130101; B68G 7/04 20130101; B29C 41/003
20130101; B68G 11/04 20130101; B29K 2007/00 20130101; A47C 27/14
20130101; B29C 41/28 20130101; B29C 41/46 20130101; B29K 2105/04
20130101 |
International
Class: |
A47C 27/14 20060101
A47C027/14; B29C 41/00 20060101 B29C041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2012 |
EP |
12189608.8 |
Claims
1. A method for producing a bedding product comprising at least a
foamed latex layer, said method comprising the steps of: pouring
liquid latex foam on a conveyor belt; vulcanizing said liquid latex
foam in a vulcanization station to obtain a vulcanized latex foam
slab; and cutting said vulcanized latex foam slab to a desired
length and/or width, characterized in that for at least partially
vulcanizing said liquid latex foam electromagnetic waves with a
frequency ranging between 1 and 50 Mhz are used.
2. The method according to claim 1, wherein vulcanizing the latex
foam is performed subsequently by means of electromagnetic waves
and by means of steam.
3. The method according to claim 1, wherein vulcanization is solely
performed by the means electromagnetic waves whereby the specific
power of a electromagnetic wave generator used is chosen between
0.5 and 5 kW/kg latex in the vulcanization station.
4. The method according to claim 1, wherein the liquid latex foam
is poured on the carrier to a thickness of 1 cm or more, preferably
6 cm or more, most preferably 8 cm or more.
5. The method according to claim 1, wherein the liquid latex foam
is poured on a layer of foam of a material chosen from the group
comprising: polyurethane, polyolefin, polystyrene, visco-elastic
latex, gelatinized but not fully vulcanized latex and or mixtures
thereof.
6. A slab of vulcanized latex foam for cutting several bedding
products therefrom, having a thickness of 6 cm or more, preferably
8 cm or more.
7. The slab of vulcanized latex foam accordingly to claim 6
comprising a locally profiled surface.
8. A bedding product comprising at least a foamed latex layer, said
layer having a compression set of less than 10%, preferably less
than 6% after compressing the layer to 50% of its initial thickness
for 24 hrs at 70.degree. C.
9. The bedding product according to claim 8, wherein the foamed
latex layer has a thickness between 1 and 24 cm, preferably a
thickness of 6 cm or more, most preferably a thickness of 7 cm or
more.
10. The bedding product according to claim 9, wherein the foamed
latex layer has a density of less than 60 kg/m.sup.3.
11. The bedding product according to claim 9, being a mattress or a
topper.
12. A device for continuously vulcanizing latex foam, comprising an
endless belt, a device for pouring liquid latex foam on said belt,
a vulcanization station provided along said belt comprising a
electromagnetic wave generator for electromagnetic waves having a
wave length between 1 and 50 Mhz.
13. The device according to claim 12 comprising a second
vulcanization station provided along said belt and downstream from
said first vulcanization station, the second vulcanization station
being steam heated.
Description
TECHNICAL FIELD
[0001] The present invention concerns bedding products and in
particular mattresses and toppers, comprising a foamed latex
layer.
BACKGROUND OF THE INVENTION
[0002] Bedding products such as toppers and mattresses made of
latex foam are generally manufactured by steam vulcanization.
Toppers having a thickness of maximally 6 cm are known which are
produced in a continuous vulcanization process, whereby liquid
latex foam is poured onto an endless belt or carrier and is
subsequently passed through a steam oven. Above 6 cm thickness,
continuous vulcanization is not possible because heat cannot be
introduced into the core of the latex material sufficiently quickly
due to the absence of aluminium pins on the conveyor belt.
[0003] Furthermore, when manufacturing latex foam layers by steam
vulcanization it has been observed that the foam cell diameter and
the foam density varies throughout the thickness of the layer which
is undesirable for fine-tuning the properties of the latex foam
layer, such as compression set and indentation load deflection
values.
[0004] In order to address the above drawbacks, EP 1,904,570
discloses a composite foam comprising a top layer of latex foam and
a second layer of a foam selected from either latex foam or another
foam.
[0005] CA 2,007,548 discloses a method of manufacturing latex foam
mattresses with a thickness up to 15 cm thick in a batch process
whereby liquid latex foam is charged into a mold that is
subsequently brought into a microwave field having a frequency of
2,45 Ghz (example 1) and a power of 1,2 kW/ kg latex charged.
[0006] Accordingly, there remains a need for a continuous method of
manufacturing a latex layer having a uniform cell diameter, uniform
foam density, low compression set and low indentation load
deflection values and which can be produced in a thickness varying
from about 1 cm up to 24 cm or more.
DETAILED DESCRIPTION OF THE INVENTION
[0007] Definitions:
[0008] Toppers for use in bedding or seating products are known.
These toppers extend across the entire width and length of the
particular bedding or seating product. If the particular bedding or
seating product is a mattress, typically one such topper is placed
on one side of the mattress core, in particular the top side of the
mattress which is the side where a person is meant to lie upon, and
optionally a second topper is placed on the opposite side of the
mattress core, thereby effectively "sandwiching" the mattress core.
This combination then typically is covered with an upholstered
fabric covering.
[0009] "Latex" is herein defined as a dispersion of polymeric
particles in a continuous phase, the polymeric particles preferably
having a size range of from 10 to 1000 nm. The latex foam material
can be prepared from natural rubber latex or from one or more of
such synthetic latexes as polybutadiene/styrene latex,
polybutadiene/acrylonitrile latex, polychloroprene latex and the
like or from a mixture of natural rubber latex and one or more such
synthetic latexes. The latex foam includes conventional latex foam
as well as visco-elastic latex foam.
[0010] The solids content of suitable aqueous latexes is from 20 to
75% by weight. Preferred latexes have a solid content of from 50 to
75% by weight.
[0011] Suitable polymer latexes are all dispersions in which the
solid is dispersed in a liquid phase and this phase in turn forms
an emulsion with a further liquid phase. Examples are latexes of
polymers consisting of dienes or olefinically unsaturated monomers
and copolymers thereof, such as polystyrene-butadiene latex,
polybutadiene latex, polyisoprene latex, natural rubber latex,
acrylonitrile-butadiene latex, polychloroprene latex,
polydichlorbutadiene latex, latex of a copolymer of chloroprene and
dichlorobutadiene, polyisoprene latex, latex of chlorinated
polyisoprene or (meth)-acrylate latex. Dispersions of polyurethanes
or other dispersions in which polymers are dispersed in water with
the aid of emulsifiers or dispersing agents are also suitable,
however.
[0012] Preferred latexes include latexes of natural rubber,
styrene-butadiene rubber (SBR), SBR having low styrene content (up
to 27%), nitrile rubber (NBR), isoprene rubber, neoprene rubber,
polybutadiene rubber, isobutylene-isoprene rubber (IIR), copolymers
of acrylonitrile, methacrylonitrile, acrylates, methacrylates,
vinylpyridine with butadiene or 2- chloro-1, 3-butadiene and
chlorinated polyethylene or mixtures of any of these.
[0013] Highly preferred are latexes of natural rubber,
styrene-butadiene rubber, nitrile rubber, polybutadiene rubber,
isoprene rubber or copolymers comprising acrylates.
[0014] Polymer-containing latexes, such as e.g. SBR
(styrene-butadiene rubber) or NBR (acrylonitrile-butadiene rubber),
polychloroprene, polybutadiene, polyisoprene, natural rubber latex,
polyvinyl chloride, (meth)-acrylate dispersions or dispersions of
copolymers thereof, are conventionally available commercially in
solids concentrations of more than 50%. These concentrations can be
achieved e.g. by increasing the concentration of low-concentration
polymer latexes. The concentration of natural rubber latex is
increased from 30% to 60% solids, for example.
[0015] Other preferred latexes are combinations of synthetic and
natural latex. Preferred proportions of natural latex to synthetic
latex can be varied from 1:4 to 6:4. Highly preferred proportions
of natural to synthetic latex are more than 1:1.
[0016] The proportions should be optimized according to the latex
used.
[0017] A method according to the present invention can be carried
out using a device comprising an endless belt, means for pouring
liquid latex foam on said belt, a vulcanization station provided
along said belt comprising a electromagnetic wave generator for
electromagnetic waves having a frequency between land 50 Mhz.
[0018] Optionally the device may comprise a second vulcanization
station provided along said belt and downstream from said first
vulcanization station, the second vulcanization station being steam
heated.
[0019] The method according to the present invention for producing
a bedding product comprises at least a foamed latex layer, said
method comprising the steps of: [0020] pouring liquid latex foam on
a conveyor belt; [0021] vulcanizing said liquid latex foam in a
vulcanization station to obtain a vulcanized latex foam slab;
[0022] cutting said vulcanized latex foam slab to a desired length
and/or width, whereby for at least partially vulcanizing said
liquid latex foam electromagnetic waves with a frequency ranging
between 1 and 50 Mhz are used.
[0023] According to a first method the liquid latex foam is
vulcanized up to a desired level solely by the use of
electromagnetic waves, preferably in one single vulcanization
station through which the conveyor belt is moved.
[0024] In this first method, vulcanization can be obtained in a
period of several minutes by applying specific power of a
electromagnetic wave generator used is chosen between 0.5 and 5
kW/kg latex in the vulcanization station.
[0025] Alternatively the vulcanization can be performed by means of
electromagnetic waves up to a point wherein the foam layer is
dimensionally stable and subsequently finished in a second
vulcanization station wherein for example steam is used for heating
the latex foam.
[0026] The use of the electromagnetic waves for at least partially
vulcanizing the latex foam is advantageous in that foam layers
between from 1 cm to more than 6 cm, preferably even more than 8 cm
and most preferably up to even 24 cm in thickness can be vulcanized
showing good performance in uniform cell diameter, uniform foam
density, low compression set (lower than 10%) and low indentation
load deflection values. Foam densities of as low as 40 kg/m.sup.3
are achievable with the method according to the present
invention.
[0027] According to an alternative method, the liquid latex layer
can be poured upon a preformed foam layer provided on the endless
conveyor belt, said preformed foam layer being made form a material
chosen from the group comprising: polyurethane, polyolefin,
polystyrene, visco-elastic latex, dimensionally stable gelatinized
but not fully vulcanized latex and or mixtures thereof.
[0028] In case the second layer is a gelatinized but not fully
vulcanized latex layer, vulcanization of the second layer can be
obtained in the vulcanization station used for vulcanizing the
poured liquid latex foam layer.
[0029] Extensive trials with the method according to the present
invention have shown that latex foam layer can be obtained with a
50% improvement in compression set (ISO1856) in view of latex foam
layers vulcanized with steam vulcanization only. Other advantages
of latex foam layers obtained by a method according to the present
invention vs latex foam layers obtained by steam vulcanization
alone include: improved resistance to loss of hardness for over
more than 60000 cycles (ISO1957); improved tensile strength
(ISO1798); lower correlation between density and hardness in the
sense that lower foam densities can be achieved for a same
hardness; improved thermoregulation (better heat absorption
resulting in a improved comfort perception and faster adaptation of
the foam latex to the body temperature of a person lying on the
foam); and improved water absorption (up to 10% better water
absorption without impact on the desorption rates).
[0030] Finally it has been found that by applying stamps on the
latex foam layer during vulcanizing said liquid latex foam
electromagnetic waves with a frequency ranging between 1 and 50
Mhz, patterns are created in the final foam layer, making it
possible to personalize the outer surface of the latex layer
easily, for example by providing a profiled logo in the top surface
of the latex foam layer.
EXAMPLES
Example 1
[0031] A natural latex foam was prepared according to a known
formula and poured on an endless belt between two side rims having
a height of 26 cm along which a vulcanization station powered with
an electromagnetic waves generator preset on 2.7 Mhz and a specific
power of 2 kW/kg latex present in the vulcanization station. The
vulcanization station has a length of 8 m, while the endless belt
is set to move at a speed of 0.4 m/minutes.
[0032] At the exit of the vulcanization station, the vulcanized
latex foam slab has thickness of 24 cm and is cut into toppers of 1
m by 2 m. Several toppers where analyzed and showed low compression
set and uniform foam density (weights of several toppers where very
similar). The compression set was measured by compressing the
topper to 50% of its initial thickness for 24 hrs at 70.degree. C.
and subsequently releasing pressure, whereby after 0.5 hours the
thickness was measured. The compression set is defined as the loss
in thickness after compression expressed in %. All results were
between 5 and 6% loss in height.
* * * * *