U.S. patent application number 12/677212 was filed with the patent office on 2010-12-09 for improvement to a plastic part of a protective helmet.
This patent application is currently assigned to MSA GALLET. Invention is credited to Louis Guay, Philippe Vigouroux.
Application Number | 20100306903 12/677212 |
Document ID | / |
Family ID | 39291613 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100306903 |
Kind Code |
A1 |
Guay; Louis ; et
al. |
December 9, 2010 |
IMPROVEMENT TO A PLASTIC PART OF A PROTECTIVE HELMET
Abstract
The invention relates to a plastic part of a protective helmet,
characterised in that the parts undergo a treatment in order to
improve the technical specifications thereof, in particular the
mechanical strength of a part of a protective helmet at low and
high temperatures, said treatment comprising the application of
ionising radiation to the parts.
Inventors: |
Guay; Louis; (Chatillon Sur
Chalaronne, FR) ; Vigouroux; Philippe; (Chalon Sur
Saone, FR) |
Correspondence
Address: |
CANTOR COLBURN LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
MSA GALLET
CHATILLON SUR CHALARONNE
FR
|
Family ID: |
39291613 |
Appl. No.: |
12/677212 |
Filed: |
September 5, 2008 |
PCT Filed: |
September 5, 2008 |
PCT NO: |
PCT/FR08/01239 |
371 Date: |
August 20, 2010 |
Current U.S.
Class: |
2/410 |
Current CPC
Class: |
A42C 2/00 20130101; A42B
3/06 20130101 |
Class at
Publication: |
2/410 |
International
Class: |
A42B 3/04 20060101
A42B003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2007 |
FR |
07/06335 |
Claims
1. A plastic part of a protective helmet, characterized in that the
parts are subjected to a treatment to improve their technical
characteristics and in particular the mechanical strength at low
and high temperatures of a part of a protective helmet, said
treatment consisting in subjecting these parts to ionizing
radiation.
2. The plastic part of a protective helmet as claimed in the
preceding claim, characterized in that the part is made of plastic
of the thermoplastic type.
3. The plastic part of a protective helmet as claimed in the
preceding claim, characterized in that the part is made of plastic
of the thermoplastic type of the polyamide 6 (PA-6) type.
4. The plastic part of a protective helmet as claimed in claim 2,
characterized in that the part is made of plastic of the
thermoplastic type of the polyamide 6,6 (PA-6,6) type.
5. The plastic part of a protective helmet as claimed in the
preceding claim, characterized in that the part is an outer shell
of a protective helmet made of thermoplastic.
6. The plastic part of a protective helmet as claimed in any one of
the preceding claims, characterized in that the ionizing radiation
is electron ionization.
7. The plastic part of a protective helmet as claimed in any one of
claims 1 to 5, characterized in that the ionizing radiation is
photon ionization.
8. Process for producing parts as claimed in any one of the
preceding claims, characterized in that the process comprises the
following steps: in a preliminary first step, the parts are
produced from plastic, for example by thermoplastic injection
molding, in a second step, the parts are introduced into an
ionizing chamber in order to be subjected to ionizing radiation,
and in a third step, the parts, once they have been ionized, are
removed.
9. The process as claimed in the preceding claim, characterized in
that, before the injection molding, a coagent is introduced into
the formulation, the aim of the coagent being to enable the
bridging of macromolecular chains while the double bonds of which
it is composed are opened.
10. The process as claimed in the preceding claim, characterized in
that coagent is from the methacrylate or allyl family.
11. The process as claimed in the preceding claim, characterized in
that the volume of incorporation of the coagent into the
formulation is between 0.05% and 10% by weight.
Description
[0001] The present invention is in the field of the production of
plastic parts and more particularly the production of plastic parts
of a protective helmet. According to the invention, a process is
provided for treating these materials in order to improve their
strength at low and high temperatures.
[0002] The parts of a protective helmet are intended more
particularly for firefighters' helmets and are in particular the
outer shell thereof and the plastic parts associated therewith,
such as the parts for holding the chinstrap or the breathing mask,
for example, or the pivot pins for protective shields, inner
headband, etc.
[0003] Protective helmets, in particular firefighters' helmets,
have a shell produced from thermoplastic and are currently made
either of polyamide or an
acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC) alloy. It is
difficult to reconcile the resistance at high temperature, for
example at +120.degree. C., with the resistance at low temperature,
such as in particular at -40.degree. C., of one and the same
thermoplastic.
[0004] Of course, the parts of which the helmet consists could be
made of a different material, for example metal, curable polymer or
high-performance thermoplastic, such as polyphthalamide (PPA),
polyethylene sulfone (PES), polyetheretherketone (PEEK). However,
in the case of a protective helmet, weight is an important factor,
as is the manufacturing cost.
[0005] The present invention aims to solve the abovementioned
problems by providing a particularly simple and effective process
for giving the helmet parts produced from thermoplastic qualities
identical to those they would have if they were produced from other
materials such as thermosetting plastic, for example.
[0006] Thus, according to the invention, the helmet parts made of
thermoplastics are ionized, it being known that ionization is a
process which is essentially only used for sterilizing medical and
surgical material and for preserving agricultural food
products.
[0007] It is known that at low temperatures, the impact properties
are worse, while at high temperatures the mechanical strength is
greatly reduced. The parts treated according to the invention have
mechanical characteristics around 5 to 10% better for the same
range of temperatures, and the novel mechanical characteristics
make it possible to use the helmet in a wider range of uses.
[0008] In summary, the protective helmet produced according to the
invention has a greatly improved cold and heat resistance, and this
is particularly advantageous for a firefighter's helmet. Thus,
according to the invention, the plastic part of a protective helmet
is characterized in that it is subjected to a treatment to improve
its technical characteristics and in particular the mechanical
strength at low and high temperatures of a part of a protective
helmet, said treatment consisting in subjecting these parts to
ionizing radiation.
[0009] According to a complementary characteristic, the part is
made of plastic of the thermoplastic type, such as of thermoplastic
of the polyamide 6 (PA-6) type, for example, or of polyamide 6,6
(PA-6,6).
[0010] According to another characteristic, the part is an outer
shell of a protective helmet made of thermoplastic.
[0011] It may be added that, according to the invention, the
ionizing radiation is electron ionization or photon ionization.
[0012] The invention also relates to the process for producing
parts, which comprises the following steps: [0013] in a preliminary
first step, the parts are produced from plastic, for example by
thermoplastic injection molding, [0014] in a second step, the parts
are introduced into an ionizing chamber in order to be subjected to
ionizing radiation, and [0015] in a third step, the parts, once
they have been ionized, are removed.
[0016] According to a complementary characteristic of the process,
before the injection molding, a coagent is introduced into the
formulation, the aim of the coagent being to enable the bridging of
macromolecular chains while the double bonds of which it is
composed are opened.
[0017] Further characteristics and advantages of the invention will
emerge from the following description.
[0018] The plastic parts of the protective helmet, such as its
shell and/or its accessories and various parts associated with it,
which are produced with a thermoplastic, are subjected according to
the invention to a treatment intended to improve their resistance
to both low and high temperatures, these parts not having this
resistance without having been subjected to the treatment of the
invention.
[0019] The treatment of the invention consists in a process
utilizing ionizing radiation, which, with sufficient energy, gives
rise to reactive entities known as ions within the material. In the
case of the plastic of the helmet and its accessories or associated
parts, the ions are immediately converted into active free
radicals, which by combining create new permanent chemical
bonds.
[0020] The plastic parts of the helmet of the invention are made
for example of a thermoplastic polymer, such as polyamide (PA), and
are advantageously of the polyamide 6 (PA-6) or the polyamide 6,6
(PA-6,6) type, these being materials which react perfectly with
electrons; the material could, however, be of the polyamide 4,6
(PA-4,6) or polyamide 11 (PA-11) type.
[0021] Two types of ionization may be used for the process of the
invention, namely electron ionization (beta treatment) or photon
ionization (gamma treatment).
[0022] In the course of electron ionization, the electrons emitted
by an electric source lose some of their kinetic energy each time
they collide with an atom of the part treated.
[0023] In the course of photon ionization, the photons emitted by a
radioactive source move the electrons in order to create ions.
[0024] Crosslinking by ionization increases the choice of
materials. Thus, the protective helmet and/or its attachments may
be produced from thermoplastic and crosslinking by ionization gives
these parts an identical strength to that of thermosetting polymers
or high performance thermoplastics (PPA, PES, PEEK).
[0025] Thus, the parts produced and crosslinked by ionizations are
lighter for given characteristics and their preparation, for
example by injection molding, is easier, with a reduced cycle
time.
[0026] According to the process of the invention, the sharp melting
point of the material is eliminated, thereby giving the material
improved stability of mechanical properties at high
temperatures.
[0027] During ionization, bridging of molecular chains takes places
and this tends to give the thermoplastic the same behavior as a
thermosetting plastic.
[0028] The process for treating parts comprises the following
steps:
[0029] In a preliminary first step, the parts are produced from
plastic, for example by thermoplastic injection molding, such as
from polyamide 6 or polyamide 6,6, for example.
[0030] The parts are produced, for example, by injection molding on
the basis of granules of the abovementioned materials. A coagent
has previously been introduced into the formulation, the aim of the
coagent being to enable the bridging of macromolecular chains while
the double bonds of which it is composed are opened. The use of a
coagent in the formulation also brings about a substantial lowering
of the amount necessary for crosslinking the macromolecular chains.
The preferred coagents are from the methacrylate or allyl family.
The volume of incorporation of the coagent into the formulation is,
for example, between 0.05% and 10% by weight.
[0031] In a second step, the parts are introduced into an ionizing
chamber in order to be subjected to ionizing radiation.
[0032] In a third step, the parts, once they have been ionized, are
removed.
[0033] It has been understood that, by virtue of the ionizing
treatment, the impact strength of the part treated by ionization is
improved, and particularly its low-temperature impact strength. It
is noted that in order to increase the low-temperature impact
strength of a polyamide of the PA-6 or PA-6,6 type it is possible
to use two treatment techniques: [0034] either grafting linked to
the exposure of the material to radiation, such as with compounds
of ethylene dimonomer (EPDM) or copolyamides-6,12 (CoPA-6,12) or
else thermoplastic polyester elastomers (TPE-E).
[0035] Of course, the invention is not limited to the embodiments
described and shown by way of example, but also comprises all the
technical equivalents and their combinations.
* * * * *