U.S. patent application number 10/053129 was filed with the patent office on 2003-02-27 for fabricated resin products for laser welding and including transmitting and absorbing black colorants, and colored resin compositions therefor.
Invention is credited to Hatase, Yoshiteru, Hayashi, Ryuichi, Koshida, Reiko.
Application Number | 20030039837 10/053129 |
Document ID | / |
Family ID | 22935740 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030039837 |
Kind Code |
A1 |
Koshida, Reiko ; et
al. |
February 27, 2003 |
Fabricated resin products for laser welding and including
transmitting and absorbing black colorants, and colored resin
compositions therefor
Abstract
Novel fabricated resin products are described and having
suitability for laser welding applications. These contain a resin
part for transmitting black colorant and a resin part for absorbing
black colorant.
Inventors: |
Koshida, Reiko; (Utsunomiya,
JP) ; Hatase, Yoshiteru; (Osaka, JP) ;
Hayashi, Ryuichi; (Tokyo, JP) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY
LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
22935740 |
Appl. No.: |
10/053129 |
Filed: |
November 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60247648 |
Nov 13, 2000 |
|
|
|
Current U.S.
Class: |
428/411.1 ;
428/474.4; 428/480; 524/357; 524/358 |
Current CPC
Class: |
B29C 66/73321 20130101;
B29C 65/1677 20130101; Y10T 428/31786 20150401; B29C 66/7315
20130101; B29C 65/1658 20130101; B29K 2309/08 20130101; B29C 66/712
20130101; B29K 2995/002 20130101; B29C 66/73362 20130101; B29C
66/12841 20130101; Y10T 428/31725 20150401; B29K 2995/0073
20130101; Y10T 428/31504 20150401; B29C 66/43 20130101; B29C 66/71
20130101; B29C 66/14 20130101; B29C 66/73361 20130101; B29C
66/73921 20130101; B29K 2105/0032 20130101; B29C 65/1687 20130101;
B29C 66/1282 20130101; B29C 65/1616 20130101; B29C 65/8207
20130101; B29C 65/1635 20130101; B29C 65/8215 20130101; B29C
65/8253 20130101; B29C 66/836 20130101; B29K 2105/06 20130101; B29K
2995/0022 20130101; B29C 65/1674 20130101; B29K 2995/0027 20130101;
B29C 66/71 20130101; B29K 2077/00 20130101; B29C 66/71 20130101;
B29K 2067/00 20130101; B29C 66/71 20130101; B29K 2067/003 20130101;
B29C 66/71 20130101; B29K 2069/00 20130101; B29C 66/71 20130101;
B29K 2067/006 20130101 |
Class at
Publication: |
428/411.1 ;
428/474.4; 428/480; 524/357; 524/358 |
International
Class: |
C08K 005/08; B32B
027/34; B32B 027/36 |
Claims
1. A fabricated resin product for laser welding comprising: a first
laser beam transmitting resin part comprising laser-beam
transmitting black colorant which absorbs visible light of
wavelength of less than 700 nm and transmits a laser beam at
wavelength in the range of 800 nm to 1200 nm, and a second laser
beam absorbing resin part comprising laser-beam absorbing black
colorant, wherein said first resin part is joined to said second
resin part by a laser beam transmitted through said resin part and
absorbed in said second resin part.
2. The fabricated resin product of claim 1 where said resin part is
polyamide or polyester.
3. The fabricated resin product of claim 2 wherein said resin part
is a polyester resin selected from the group consisting of
polyethylene terephtalate, polypropylene terephthalate,
polybutylene terephthalate, polyethylene 2,6-naphthalate,
polycyclohexane dimethylene terephthalate and copolymers and
mixtures thereof.
4. A resin composition suitable for transmitting a laser beam,
comprising a resin and laser beam transmitting colorant and having
a transmission rate ratio (T.sub.black resin for laser
transmissionT.sub.natural resin) of 0.5-1.2 wherein the
transmission rate of said resin composition containing said black
colorant is compared to the transmission rate of said resin alone
for laser beams with wavelength at 1064 nm.
5. The composition of claim 4 wherein said transmission rate ratio
is 0.5-1.2 for laser beams with wavelength at 940 nm.
6. The composition of claim 4, wherein said composition comprises
said laser beam transmitting black colorant comprising the
inorganic salts in amount of less than 2 weight percent.
7. The composition of claim 5 wherein said composition comprises
said laser beam transmitting black colorant comprising the
inorganic salts in amount of less than 2 weight percent.
8. The composition of any of claims 4-5 wherein said composition
comprises said laser beam transmitting black colorant comprising Ca
in amount less than 5000 ppm.
9. The composition of any of claims 4-5 in which said laser beam
transmitting black colorant is a blend of blue dye or green dye
with red dye and optionally yellow dye.
10. The composition of any of claims 4-5 in which said laser beam
transmitting black colorant comprises an anthraquinone dye.
11. The composition of any of claims 4-5 in which said laser beam
transmitting black colorant is a blend of blue dye or green dye of
anthraquinone dye, red dye of perinone, dye and yellow dye.
12. The composition of any of claims 4-5, in which said laser beam
transmitting black colorant comprises monoazo complex dye.
13. A resin composition suitable for absorbing a laser beam,
comprising a resin and laser-beam absorbing colorant, and having a
transmission rate ratio (T.sub.black resin for laser
transmissionT.sub.natural resin) of 0-0.2 and wherein the
transmission rate of said resin composition containing said laser
beam absorbing black colorant is compared to the transmission rate
of resin alone.
14. The composition of claim 13 wherein said laser beam absorbing
black colorant further comprises at least one black colorant
selected from the group consisting of carbon black, phthalocyanine
compounds, nigrosine dyes and aniline black.
15. The composition of claim 13 in which the said laser beam
absorbing black colorant comprises a mixture of carbon black and
nigrosine dye.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/247,648, filed Nov. 13, 2000.
FIELD OF THE INVENTION
[0002] This invention relates to fabricated resin products useful
for laser welding applications, where laser light melt-bonds a
portion of or all of the contact surfaces of multiple resin parts.
More particularly, this invention pertains to fabricated resin
products for laser melt-bonding where the contact surface between
resin parts having laser-transmitting black colorants and
laser-absorbing black colorants respectively is welded.
BACKGROUND OF THE INVENTION
[0003] In recent years many fabrication methods have been designed
to form complicated shapes of resin compositions such as the hollow
parts and tubes in various industrial applications. However, there
are certain limitations to these existing methods.
[0004] Many fabrication methods rely on adhesives for their sealing
properties, but these are time-consuming and costly, and pose
environmental concerns due to the use of volatile solvents.
Ultrasonic welding or spin welding suffer from limitations on the
shape and size of the objects bonded together, and occasionally
show insufficient bonding strength. Vibration welding is often
unattractive due to the inability to effectively control product
appearance and flash, thereby limiting usage to certain
applications.
[0005] Hence, the laser welding is increasingly attractive as a new
method to better cope with these drawbacks. In laser welding, a
laser light is irradiated through a transmitting resin material
onto an absorptive resin material attaching to the resin material.
The energy of the laser light accumulated on the contacting part of
the absorptive resin material heats and melts the contacting part
and the transmitting resin material is also heated and melted
through heat transfer. The result of this operation is that the
resin materials are easily and strongly joined together.
[0006] Another benefit to laser welding is that it increasingly
offers freedom of choice in designing the shape of the joined
articles because energy is applied in a noncontact fashion for the
finishing product to be melted/bonded.
[0007] Several important laser welding methods rely on Nd:YAG
lasers (or known simply as YAG lasers) or diode lasers as the laser
beam source, and these lasers emit light in the near infrared
region. The diode laser techniques have become particularly
advanced in recent years and diode lasers with higher output power
can be obtained at lower cost.
[0008] Many materials may benefit from welding techniques using
such lasers. For example, polyethylene resin, polypropylene resin,
polystyrene resin, polycarbonate resin, acrylic resin and nylon
resin have been demonstrated as effective candidates for laser
welding. Thermoplastic resin compositions useful in laser welding
are described, for example, in Japanese Published (Koukoku) Patent
No.62-49850 and Japanese Published (Koukoku) Patent No.5(93)-42336.
Other resin compositions associated with the laser welding are
described in U.S. Pat. No. 5,893,959 in which carbon black or
nigrosine is used as a colorant for thermoplastic resin.
[0009] If there are many efforts directed to the laser welding of
nylon resins. In conventional laser welding, laser beams penetrate
through a laser transmitting article positioned close to a laser
beam source, and are largely absorbed in the laser absorbing
article disposed in contact with the laser transmitting article.
This causes the junction portion to be melted and jointed together.
However, non-colored resins have been used as the transmitting
resin material. The use of such materials limits their
applicability for articles of various colors demanded in the
automotive industry and electric/electronic industries. Of
particular interest, the use of black material in these
applications is not satisfactorily popularized at this time using
conventional laser welding operations. Additionally, there are some
suggestions that black pigment can be diluted and utilized in part
of the transmitting resin or even using materials in a thinner
shape to facilitate transmission. However such approaches cannot
ensure the satisfactory appearance of the resulting part and do not
allow much flexibility in designing parts. There are still other
examples suggesting the addition of carbon black to the absorptive
resin as an approach. However the details of such an approach are
not yet fully understood or functional.
[0010] The present invention provides a thermoplastic resin
composition capable of offering molded articles which appear in
black, are transparent to a laser beam at wavelengths in the
infrared region. As another feature, it provides a substantially
homogenous visual black impression in combination with opaque
articles that appears in black and absorbs the laser beam largely
by containing black dyes, welded together by the laser beam. These
materials offer advantages in excellent and balanced
heat-resistance and mechanical properties as required in automotive
parts, electric/electronic components, mechanical components, and
many other applications. These and other objects, features and
advantages of the invention will become better understood upon
having reference to the following description of the invention.
SUMMARY OF THE INVENTION
[0011] The present invention for achieving the aforementioned
purpose provides fabricated resin products for laser welding, with
a resin part containing laser-transmitting black colorant and a
resin part containing laser-absorbing black colorant, and where
laser light is utilized to melt-bond a part or all of the contact
surface of the two resin parts.
[0012] A fabricated resin product is provided for laser welding
comprising:
[0013] a first laser beam transmitting resin part comprising
laser-beam transmitting black colorant which absorbs visible light
of wavelength of less than 700 nm, and transmits a laser beam at
wavelength in the range of 800 nm to 1200 nm, and a second laser
beam absorbing resin part comprising laser-beam absorbing black
colorant, wherein said first resin part is joined to said second
resin part by a laser beam transmitted through said first resin
part and absorbed in said second resin part.
[0014] There is also provided a resin composition for laser
transmission for which the transmission rate ratios (T.sub.black
resin for laser transmission/T.sub.natural resin) are 0.5-1.2 when
the transmission rates of the resin composition containing the
black colorant for laser transmission are compared to the
transmission rates of the resin composition not containing said
black colorant for laser transmission (natural resin) at 1064 nm
and at 940 nm.
[0015] And the present invention for achieving the aforementioned
purpose provides a resin composition for laser absorption for which
the transmission rate ratio (T.sub.black resin for laser
absorption/T.sub.natural resin) is 0-0.2 when the transmission rate
of the resin composition containing the black colorant for laser
absorption is compared to the transmission rate of resin
composition not containing said black colorant for laser absorption
(natural resin).
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention will become better understood upon having
reference to the drawings herein. In general, the figures depict a
laser welding test method in which welding strength between the
laser transmitting (transparent) article and laser absorbing
(opaque) article welded together by a laser welding is
measured.
[0017] FIG. 1(A) illustrates a shape and dimensions of the test
piece for the laser welding test with Examples 37-49 and
Comparative Example 50.
[0018] FIG. 1(B) is a perspective view of test pieces disposed
close to each other for a laser welding test and relationship
between the test pieces and laser beam with Examples 37-49 and
Comparative Example 50.
[0019] FIG. 2(A) illustrates a shape and dimensions of the test
piece for the laser welding test with Examples 24-28, 30-31 and
Comparative Examples 29, 32-36.
[0020] FIG. 2(B) is a perspective view of test pieces disposed
close to each other for a laser welding test and relationship
between the test pieces and laser beam with Examples 24-28, 30-31
and Comparative Examples 29, 32-36.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Useful lasers to weld the molded resin products of the
present invention may be any lasers having light emissions in the
near infrared region. Particularly, lasers emitting light of
wavelengths from 800-1200 nm are preferred, and diode lasers and
YAG lasers are particularly preferred. Lasers may be utilized
singly or in combination with each other, as will be appreciated
among those having skill in the art of laser operation. The laser
emissions may be continuous or pulsed, with continuous emissions
being preferred.
[0022] With respect to the resin materials subject to the laser
welding, there is provided one resin material that is
laser-transmitting and another resin material that is
laser-absorptive. By irradiating a laser light through the
transmitting resin material onto the absorptive resin material
attached thereto, the energy of the laser light accumulated on the
contact surface of the absorptive resin material heats and melts
the contact area. The transmitting resin material is also
heated/melted through heat transfer, so that the resin materials
are easily and strongly bonded together. The laser light may
directly irradiate the welding area or may be guided to the contact
area using an optical apparatus such as a mirror or optical fiber.
These and other techniques are employed as appropriate to the
individual welding operation, and are selected by those having
skill in this field.
[0023] The intensity, density and irradiating area of the laser is
selected to appropriately carry out the heating and melting of the
bonding surface. These are adjusted in such as a way that the
resulting bonding is obtained with the strength required for the
application of interest. If it is too weak, a sufficient heating
melting cannot be realized. Conversely if it is too strong,
degradation of resin may be induced.
[0024] The instant invention pertains to the junction portion of
two molded articles (being respectively laser-transmitting and
absorbing) positioned in contact with each other, in which a
predetermined amount of laser beam is focused and transmitted, is
melted and bonded. If a multiple number of points, lines or
surfaces are to be welded, the laser light may be moved in sequence
to irradiate the bonding surface, or a multiple laser sources may
be used to irradiate simultaneously.
[0025] The molded resin products suitable for laser welding can be
obtained by any methods including extrusion molding and injection
molding. It only requires that the molded product made with
transmitting resin for the laser utilized is in close contact with
the molded product made with the absorptive resin for the laser
utilized. If necessary, pressure can be further applied on the
bonding surface.
[0026] Also, the bonded resin products suitable for welding by
laser may be a combination of more than two parts.
[0027] For example, the invention is applicable to operations
requiring one to weld more than 2 parts in one laser welding
operation, or to weld complex configured article(s) by performing
laser welding in part successively.
[0028] The transmitting resin and the absorptive resin may be of
the same or different resins.
[0029] Also, the method may be applied in combination with or
instead of other bonding methods.
[0030] For example, portions of materials to be joined together and
where bonding techniques other than laser welding cannot be used
(because of its configuration or dimensions, etc.) may be subject
to laser welding.
[0031] The resins utilized as the molded resins for laser welding
may be any resin as long as they are thermoplastic resins.
Polyamide resins and polyester resins are preferred from the point
of view of heat-resistance and transmitting property, although
other thermoplastic resins including polycarbonate resins can be
used as well, alone, in combination with each other, or in
combination with those preferable resins above.
[0032] Several examples of polyamide resins suitable for use in the
present invention include condensation products of dicarboxylic
acids and diamines, condensation products of aminocarboxylic acids
and ring-opening polymerization products of cyclic lactams.
Examples of dicarboxylic acids useful in this application include
adipic acid, azelaic acid, sebacic acid, dodecanedioic acid,
isophthalic acid and terephthalic acid. Examples of suitable
diamines include tetramethylene diamine, hexamethylene diamine,
octamethylene diamine, nonamethylene diamine, dodecamethylene
diamine, 2-methylpentamethylene diamine, 2-methyloctamethylene
diamine, trimethylhexamethylene diamine,
bis(p-aminocyclohexyl)methane, m-xylene diamine and p-xylene
diamine. As an example of aminocarboxylic acid, 11-aminododecanoic
acid can be used. Examples of useful cyclic lactams include
caprolactam and laurolactam. Specific examples of condensation
products and ring-opening polymerization products include aliphatic
polyamides such as nylon 6, nylon 66, nylon 46, nylon 610, nylon
612, nylon 11, nylon 12, semi-aromatic polyamides such as
polymetaxylene adipamide (nylon MXD-6), polyhexamethylene
terephthalamide (nylon 6T), polyhexamethylene isophthalamide (nylon
61) and polynonamethylene terephthalamide (nylon 9T), and
copolymers and mixtures of these polymers. Examples of useful
copolymers include nylon 6/66, nylon 66/6I, nylon 6I/6T and nylon
66/6T.
[0033] A wide range of common polyester molding compositions useful
for blending with colorants in the practice of the present
invention are known in the art. These include polymers which are,
in general, condensation products of dicarboxylic acids and diols.
Dicarboxylic acids can be selected from the group consisting of
adipic acid, azelaic acid, sebacic acid, dodecanedioic acid,
terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid
and diphenyl dicarboxylic acid, and diols can be selected from the
group consisting of ethylene glycol, propylene glycol, butanediol,
hexanediol, neopentyl glycol, cyclohexanediol, and bisphenol A.
Preferred polyesters include polyethylene terephtalate (PET),
polypropylene terephthalate (3GT), polybutylene terephthalate
(PBT), polyethylene 2,6-naphthalate (PEN), polycyclohexane
dimethylene terephthalate (PCT) and copolymers and mixtures
thereof. As the examples of the copolymers, some of dicarboxylic
acids or some of diols can be added to the condensation products.
Polyester polymers may be copolymerized a little amount of
compnents like trimesic acid, trimellitic acid, pyromellitic acid,
glycerol, and pentaerythritol which have more than 3 functional
groups.
[0034] Additional other polymers including polycarbonate can also
be presented, provided that the essential characteristics of the
composition of the present invention are not substantially
altered.
[0035] The resin composition for laser transmitting utilized in the
fabricated resin products for laser welding contain at least a
laser-transmitting black colorant and thermoplastic resin.
[0036] The amount of incorporation of the laser-transmitting black
colorants in the resin compositions for transmission is 0.01-15
weight percent, and preferably 0.05-5 weight percent, versus based
upon 100 weight percent thermoplastic resin.
[0037] The laser-transmitting black colorants utilized in the
present invention show absorption in the visible light region
(400-700 nm) and have transmitting property from the diode laser to
the near YAG laser area (800-1200 nm).
[0038] All dyes that show partial absorption in the visible light
region (400-700 nm) and have transmitting properties from the diode
laser to the near YAG laser area (800-1200 nm) can be utilized as
the aforementioned black colorant. As an example, blending two or
more of such dyes having a single structure for absorption in the
visible light region to give a mixed black color dye having
absorption in the visible light region may be used.
[0039] There are many examples of combinations of mixed dyes useful
in this invention. For instance, the combination of blue dye, red
dye and yellow dye; the combination of green dye, red dye and
yellow dye; the combination of blue dye, green dye and red dye and
yellow dye; and the combination of green dye, violet dye and yellow
dye can be used. However, the ratio of incorporation for each dye
is appropriately adjusted based on the color tone of the dye, the
resin utilized and the concentration (or the thickness of the
resin) utilized. Generally, the dyes which exhibit blue, violet and
green colorant can be main components to produce the black dyes.
They may be used one or more two and be included more than 50% in
the black dyes.
[0040] Of particular significance, the black colorant for laser
transmission shows high transmitting properties near the YAG laser
region and when the transmission rate ratio (T.sub.black resin for
laser transmission/T.sub.natural resin) is 0.5-1.2, preferably
0.8-1.2. This occurs when the transmission rate of the resin
composition containing the black colorant for laser transmission is
compared to the transmission rate of the resin composition not
containing said black colorant for laser transmission (natural
resin) at 1064 nm.
[0041] The transmission rates of the aforementioned resin
compositions for laser transmission are preferably between 940 and
1064 nm.
[0042] Of particular significance, when anthraquinone blue-violet
dyes are chosen and blended with at least one dye absorbing in the
visible light region outside the visible light region of the
aforementioned anthraquinone dyes, the resulting mixed black
colorant exhibits high transmission in the diode laser region. The
transmission rate ratio (T.sub.black resin for laser
transmission/T.sub.natural resin) in such cases is more than 0.5,
preferably 0.8-1.1, when the transmission rate of the resin
composition containing the black colorant for laser transmission is
compared to the transmission rate of the resin composition not
containing said black colorant for laser transmission (natural
resin) at 940 nm. Hence, it is suitable for laser welding with a
diode laser.
[0043] As examples of the dyes to obtain black colorant for laser
transmission monoazo complex dyes, anthraquinone dyes, perinone
dyes and quinophthalone dyes can be used. In the present invention,
these dyes can be used singly or in combination.
[0044] By changing the structure of the aforementioned
anthraquinone dyes, various colors such as yellow, red, blue,
violet and green color can be shown, and they can be used singly or
in combinations of two or more dyes. By using the blue color,
violet color, or green color of the aforementioned anthraquinone
dyes as the dye for the longer wavelength side of the visible light
and by mixing at least one dye of the short wavelength region of
the visible light, black colorants having excellent transmission in
the entire region of the diode laser to near YAG laser (800-1200
nm) can be obtained. However, the ratio of incorporation for each
dye is appropriately adjusted based on the color tone of the dye,
the resin utilized and the concentration (or the thickness of the
resin) utilized.
[0045] As an example of a preferred formulation, a black colorant
containing at least an anthraquinone blue or green dye and perinone
red dye, and black colorant containing at least an anthraquinone
blue or green dye and monoazo complex red dye can be used. The
aforementioned formulations may contain yellow dyes, preferably
anthraquinone yellow dyes.
[0046] Specific examples of anthraquinone dyes are as follows.
These are merely representative of a wider selection of dyes that
may be used:
[0047] Green dye: C.I. Solvent Green 3, 20, 22, 23, 26, 28, 29
[0048] Blue dye:
[0049] C.I. Solvent Blue 11, 13, 14, 35, 36, 59, 63, 69, 94,
132
[0050] C.I. Vat Blue 4, 6, 14
[0051] Violet dye: C.I. Solvent Violet 12, 13, 14, 31, 34
[0052] Red dye: C.I. Solvent Red 52, 111, 114, 152, 155
[0053] Yellow dye:
[0054] C.I. Solvent Yellow 163
[0055] C.I. Vat Yellow 1, 2, 3
[0056] By changing the structure of the aforementioned monoazo
complex dyes, various colors such as yellow, red, blue, violet, and
black can be shown, and they can be used singly or in a combination
of two or more dyes. The aforementioned monoazo complex dyes have
high heat resistance and light resistance, and the molding property
and color tone for thermoplastic resins are excellent. For example,
the monoazo complex dyes represented by the following Formula (a)
are obtained by carrying out metallization of A-N=N-B monoazo dyes.
The A-N=N-B monoazo dyes are compounds obtained by carrying out
diazotization on the A component and coupling on the B component.
When pyrazolone derivatives or acetoacetanilide derivatives are
used as B components, yellow-red monoazo complex dyes are obtained,
and when naphthol derivatives are used as B components, blue-black
monoazo complex dyes are obtained. Monoazo complex dyes using
naphthols as the B components show high transmission properties
near YAG laser. In other words, black colorants having excellent
transmission in the entire region of near YAG laser (1000-1200 nm)
can be obtained by using the aforementioned monoazo complex dyes
alone or by mixing it with at least one dye with an absorption peak
at a shorter wavelength while having good transmission in the range
of 800-1200 nm. However, the ratio of incorporation for each dye is
appropriately adjusted based on the color tone of the dye, the
resin utilized and the concentration (or the thickness of the
resin) utilized. 1
[0057] In the formula, A represents an aromatic residual group
optionally having substituents, and B represents a pyrazolone
derivative residual group or acetoacetanilide derivative residual
group or naphthol derivatives residual group optionally having
substituents. M is a metal, P.sup.+ is a cation, q is an integer
0-2, and K is an integer 0-2.
[0058] As the counter ions P.sup.+ of the aforementioned monoazo
complex dyes, cations based on H.sup.+; NH.sub.4.sup.+; alkali
metals (Na, K, etc.), cations based on organic amines (primary
fatty amines, secondary fatty amines, tertiary fatty amines); and
quaternary organic ammonium ions can be used.
[0059] As the center metal M of the aforementioned monoazo complex
dyes, various metals may be used. As the more preferred ones,
metals having divalent to tetravalent atomic values can be used. As
the specific examples, Zn, Sr, Cr, Cu, Al, Ti, Fe, Zr, Ni, Co, Mn,
B, Si, and Sn can be used.
[0060] Specific examples of monoazo complex dyes are as follows.
These are merely representative of a wider selection of dyes that
may be used:
[0061] Black dye:
[0062] C.I. Solvent Black 21, 22, 23, 27, 28, 29, 31
[0063] C.I. Acid Black 52, 60, 99
[0064] Blue dye: C.I. Acid Blue 167
[0065] Violet dye: C.I. Solvent Violet 21
[0066] Red dye:
[0067] C.I. Solvent Red 8, 83, 84, 121, 132
[0068] C.I. Acid Red 215, 296
[0069] Orange dye:
[0070] C.I. Solvent Orange 37, 40, 44, 45
[0071] C.I. Acid Orange 76
[0072] Yellow dye:
[0073] C.I. Solvent Yellow 21, 61, 81
[0074] C.I. Acid Yellow 59, 151
[0075] Perinone dyes are durable dyes having excellent heat
stability, and also having excellent processing properties and
color tone for thermoplastic resins. The dyes showing red color are
particularly useful because there are very few red dyes having good
durability.
[0076] A variety of perinone dyes can be used, among them:
[0077] Violet dye: C.I. Solvent Violet 29
[0078] Red dye:
[0079] C.I. Solvent Red 135, 162, 178, 179
[0080] C.I. Vat Red 7
[0081] Orange dye:
[0082] C.I. Solvent Orange 60, 78
[0083] C.I. Vat Orange 15
[0084] Among the aforementioned perinone dyes and pigments, the
preferred dyes are identified considering their solubility and
dispersion properties in the thermoplastic resin. For example, when
dye(s) in powder form and resin(pellets) are mixed in a mixer then
such mixture is injection molded to prepare a test piece as
discussed in various examples it could be observed that the dye(s)
is well dissolved and dispersed in the resin.
[0085] Quinophthalone dyes have excellent shine appearance and are
able to give brilliant yellow color.
[0086] As specific examples of useful Quinophthalone type dyes,
Yellow Dye: C.I. Solvent Yellow 33 and 157 may be used.
[0087] It is preferable that the colorants utilized in the present
invention contain minimal inorganic salts. In the synthesis process
of dyes used in the present invention, inorganic salts are often
formed in reaction. Contamination of the inorganic salts of the
colorants in the resin compositions suppresses the growth of
crystals. In the case when there is high inorganic salt content, it
becomes particularly easy for the molded products to have cracks
and deteriorating mechanical properties. Therefore, it is
preferable that the inorganic salts are removed as much as possible
by a treating after reaction. As examples of the aforementioned
inorganic salts, chlorides of alkali metals (Li, Na, K, etc.) or
alkaline-earth metals (Ba, Ca, Sr, etc.), lead sulfate, hydroxides
can be cited.
[0088] It is preferable that the aforementioned inorganic salts are
contained in amounts under 2 percent and more preferably and under
1 percent or 0.5 percent.
[0089] It is necessary to eliminate the metals in the dye materials
serving as the dyes for the colorants utilized in the present
invention, as well as completely eliminating the salts formed and
the catalysts used in the reaction as much as possible. Also, it is
preferred to use deionized water from which metals in the
industrial water or tap water are removed, to prevent the
contamination by Ca or Fe.
[0090] Particularly, it is preferable that Ca is under 5000 ppm,
and more preferably under 3000 ppm.
[0091] The black colorants used for the absorbing part in the
present invention contain one or more dyes or pigments, which do
not transmit in the visible wavelength region, and of which at
least one absorbs laser light in the wavelength region from about
800 nm to about 1200 nm.
[0092] A number of laser-absorbing compounds known in the art can
be utilized in the instant invention. Representative examples
include carbon black, azine compounds, phthialocyanine compounds,
polymethine compounds (cyanine compounds, pyrylium compounds,
thiopyrylium compounds, squalilium compounds, croconium compounds,
azulenium compounds), diinmonium compounds, dithiol metal complex
salt compounds (M=Ni, Fe, etc.), indoaniline metal complex
compounds and mercaptonaphthol metal complex salt compounds. The
preferred compounds are carbon black, azine compounds (nigrosine
dyes, aniline black) and phthalocyanine type compounds and mixtures
thereof.
[0093] As examples of dyes or pigments having absorption in the
visible light region (400-700 nm) as well as from diode laser to
near YAG laser (800-1200 nm), carbon black, nigrosine compounds and
aniline black can be used. The aforementioned dyes or pigments can
color a resin black as appearance, highly absorbing laser
properties and having excellent laser welding by heating. However,
the ratio of incorporation for each dye is appropriately adjusted
based on the color tone of the dye, the resin utilized and the
concentration (or the thickness of the resin) utilized. The
selection of dye(s) and the amount of them can be determined
according to the application of interest and the properties
associated with the laser welding.
[0094] The amount of the laser-absorbing colorant used in the resin
composition for absorption is 0.01-15 weight percent, preferably
0.05-5 weight percent, based on 100 weight percent of thermoplastic
resin. When the amount of the laser absorbing colorant is smaller
than 0.01% in the resin composition, sufficient heat generation and
melting does not take place and welding cannot be achieved. Using
too much amount of laser-absorbing black colorant in the resin
composition is not cost effective and yields excessive heat which
causes degradation of the resin composition.
[0095] In the resin composition used for laser absorption of the
present invention, it is preferable that the transmission rate
ratio (T.sub.black resin for laser absorption/T.sub.natural resin)
is 0-0.2 when the transmission rate of the resin composition
containing the black colorant is compared to the transmission rate
of resin composition not containing said black colorant for laser
absorption (natural resin).
[0096] The resin compositions for laser absorption and the resin
compositions for laser transmission of the present invention may
optionally contain a suitable amount of various fiber reinforcing
materials. Glass fiber is preferred for a reinforced resin having a
transparency requirement. Glass fibers, alkali-containing glass,
low-alkali glass and nonalkali glass can all be used. The preferred
glass fibers are variously known as E glass and T glass. The length
and the diameter of the glass fiber that is suitably utilized are
2-15 mm and 1-20 .mu.m, respectively. There are no particular
restrictions to the shape of the glass fiber, and for example
roving fiber and milled fiber can both be used. These glass fibers
may be used alone or in a combination of two or more materials. The
fiber reinforcing materials are preferably incorporated in an
amount of 5-120 weight percent with respect to 100 weight percent
of thermoplastic resin. If this amount is under 5 weight percent,
it would be difficult to give sufficient reinforcement from the
glass fiber, and if it is over 120 weight percent, the processing
property is easily reduced. It is preferable to use levels of 5-100
weight percent, and most preferably 15-85 weight percent.
[0097] The resin compositions for laser absorption and the resin
compositions for laser transmission of the present invention may
optionally be blended with various additives if necessary. As
examples of such additives, auxiliary colorants, dispersants,
fillers, stabilizers, plasticizers, modifiers, UV absorbers or
light stabilizers, antioxidants, antistatic agents, lubricants,
releasing agents, crystallization promoters, nucleating agents,
fire retardant, and elastomers for improving impact-resistance can
be incorporated therein. These materials are added according to
conventional techniques and in amounts readily understood by those
of skill in the art.
[0098] The resin compositions for laser absorption and the resin
compositions for laser transmission of the present invention can be
obtained by blending the raw materials using conventional blending
methods, again as is understood by those of ordinary skill in the
art. These blending components in general are preferably made
homogeneous as much as possible. As a specific example, all the
materials are mixed to homogeneity using a mixer such as a blender,
kneader, Banbury mixer, roll extruder, etc. to give a resin
composition. Or, part of the materials are mixed in a mixer, and
the rest of the materials are added and further mixed until
homogeneity to yield a resin composition. Also, the materials are
dry-blended in advance and a heated extruder is used to melt and
knead until homogeneous, and is extruded in a needle shape,
followed by cutting them to a desirable length to become colored
granulates (known as a colored blend).
[0099] The master batches of the resin compositions for laser
absorption and the resin compositions for laser transmission of the
present invention can be obtained by any of a series of
conventional methods as understood by those having skill in the
art. For example, they can be obtained by mixing powders or blends
of thermoplastic resins serving as the base materials for the
master batches in a mixer such as a tumbler or super mixer,
followed by heating and melting using a extruder, a batch kneader
or a roll kneader to give pellets of rough granulates. Also, for
example, they can be obtained by adding colorants to the
synthesized or liquid thermoplastic resin for the master batch,
followed by removing the solvent to give a master batch.
[0100] Molding of the resin compositions for laser absorption and
the resin compositions for laser transmission of the present
invention can be carried out by various general methods. For
example, molding can be carried out with fabricating machines such
as extruders, inject molders and roll mill, using colored pellets.
Also, molding can be carried out by mixing pellets or powder of
thermoplastic resin having transparency, pulverized colorants and
various additives according to needs with an appropriate mixer,
followed by using a finishing machine. Also, for example, colorants
can be added to monomers containing polymerization catalysts to
prepare the desired thermoplastic resin by polymerizing this
mixture and then carry out its molding using an appropriate method.
As the examples of the molding method, the generally utilized
molding methods such as injection molding, extruding molding,
pressing molding, foaming molding, blow molding, vacuum molding,
injection blow molding, rotation molding, calendar molding and
solution casting molding can be utilized.
[0101] In FIGS. 1A and 2A herein, there is shown a lower test piece
10 used in the laser welding test of these examples. The noted
dimensions create a notch in the test piece 10. The upper test
piece 9 is of the same construction and dimensions. In FIGS. 1B and
2B there is shown the joinder of the upper test piece 9 to lower
test piece 10, and the movement of the laser 11 (in the direction
of the arrow) to form the weld.
EXAMPLES
[0102] The present invention will be better understood upon having
reference to the following examples. These are merely illustrative
of the wide range of compositions contemplated as within the scope
of the invention.
[0103] Examples 1-8 describe the black resin compositions for laser
transmission.
Example 1
[0104] In this Example and the following Examples 2-5 and 9-12,
unreinforced nylon 6 (available from E.I. du Pont de Nemours and
Co., under the product name of ZYTEL.RTM. 7301) was dried at
120.degree. C. for more than 8 hours using a vacuum drying oven.
Then the materials were apportioned and weighed according to the
specific formulation identified in each Example. The formulations
of each of the above-referenced Examples were each agitated and
mixed for 1 hour in a stainless steel tumbler.
[0105] The formulation for Example 1 is as follows:
1 Nylon 6 400 g Monoazo complex black dye of the following 0.80 g
Formula (1) (Black colorant for laser transmission)
[0106] 2
[0107] In this and all other examples 2-5, the mixture was then
injection molded to form the injection molded test specimens (whose
sizes are 48 mm.times.86 mm.times.3 mm) using K50-C produced by
Kawaguchi Steel K.K. and the cylinder temperature was set to
250.degree. C. Mold temperature was 60.degree. C. Good and
uniformly black appearance and surface gloss without color shading
of the specimens were observed.
Example 2
[0108] The following formulation was used:
2 Nylon 6 400 g Monoazo complex black dye 0.80 g
[0109] In this instance the complex dye selected was a mixed black
colorant for laser transmission having 1:1 as weight ratio of black
dye of the following Formula (2) and black dye of the following
Formula (3) 3
Example 3
[0110] The following formulation was used:
3 Nylon 6 400 g Monoazo complex black dye 0.80 g
[0111] In this example the complex dye selected was a mixed black
colorant for laser transmission having 1:1 as weight ratio of black
dye of the following Formula (4) and orange dye of the following
Formula (5) 4
Example 4
[0112] The following formulation was used:
4 Nylon 6 400 g Anthraquinone blue dye of the following Formula (6)
0.40 g Perinone red dye of the following Formula (7) 0.24 g
Anthraquinone yellow dye of the following Formula (8) 0.16 g
[0113] 5
Example 5
[0114] The following formulation was used:
5 Nylon 6 400 g Anthraquinone blue dye of the following Formula (9)
0.53 g Perinone red dye of the Formula (7) 0.18 g Anthraquinone
yellow dye of the following Formula (10) 0.09 g
[0115] 6
Example 6
[0116] In this Example and Examples 7 and 13, unreinforced
polyethylene terephthalate (PET) (prepared from terephthalic acid
and ethylene glycol the intrinsic viscosity of which is 0.85 when
measured at 25.degree. C. as a 1% solution in a mixed solution of
phenol and dichlorobenzene with the weight ratio of 1/1) was dried
at 140.degree. C. for more than 3 hours using a vacuum drying oven.
Then the materials were apportioned and weighed according to the
specific formulation identified in each such Example. Each
formulation product was agitated and mixed for 1 hour in a
stainless steel tumbler.
[0117] The formulation for Example 6 is as follows:
6 PET 400 g Monoazo complex black dye of the Formula (1) 0.53 g
Monoazo complex red dye of the following Formula (11) 0.18 g
Monoazo complex orange dye of the following Formula (12) 0.09 g
[0118] 7
[0119] The mixture was then injection molded to form the injection
molded test specimens (whose sizes are 48 mm.times.86 mm.times.3
mm) using K50-C produced by Kawaguchi Steel K.K. and the cylinder
temperature was set to 280.degree. C. Mold temperature was
60.degree. C. Good and uniformly black appearance and surface gloss
without color shading of the specimens were observed.
Example 7
[0120] The following formula was used:
7 PET 400 g Anthraquinone blue dye of the formula (6) 0.40 g
Perinone red dye of the formula (7) 0.24 g Anthraquinone yellow dye
of the formula (8) 0.16 g
Example 8
[0121] In this Example and Example 14, unreinforced polybutylene
terephthalate (PBT) (prepared from terephthalic acid and
1,4-butanediol the intrinsic viscosity of which is 1.0 when
measured at 25.degree. C. as a 1% solution in a mixed solution of
phenol and dichlorobenzene with the weight ratio of 1/1) was dried
at 140.degree. C. for more than 3 hours using a vacuum drying oven.
Then the materials were apportioned and weighed according to the
specific formulation identified in each such Example. Each
formulation product was agitated and mixed for 1 hour in a
stainless steel tumbler.
[0122] The formulation for Example 8 is as follows:
8 PBT 400 g Anthraquinone blue dye of the formula (6) 0.40 g
Perinone red dye of the formula (7) 0.24 g Anthraquinone yellow dye
of the formula (8) 0.16 g
[0123] The mixture was then injection molded to form the injection
molded test specimens (whose sizes are 48 mm.times.86 mm.times.3
mm) using K50-C produced by Kawaguchi Steel K.K. and the cylinder
temperature was set to 260.degree. C. Mold temperature was
60.degree. C. Good and uniformly black appearance and surface gloss
without color shading of the specimens were observed.
[0124] Test Procedures
[0125] (1) Determination of Transmission Rate
[0126] A 60.phi. integration ball-set for UV-visible-near infrared
region was placed in a spectrophotometer (Product of Hitachi Co.,
U-3410 model) and the experimental piece was set in, and the
transmission rate T was determined at wavelength range
.lambda.400-1200 nm.
[0127] In this case, it was focused on the transmission rate T with
the laser utilized, at .lambda.=940 nm (diode laser) and
.lambda.=1064 nm (YAG laser), and the scale for evaluation was
based on the following transmission rate ratios.
[0128] T.sub.A=T.sub.940 nm/T.sub.1064 nm
[0129] T.sub.B=T.sub.940 nm/T.sub.natural resin
[0130] T.sub.C=T.sub.1064 nm/T.sub.natural resin
[0131] (2) Test of Appearance and Evaluation
[0132] For the appearance, the reflective rate (OD value) of the
experimental piece was determined using a dual
transmission-reflection intensity meter (Product of McBase Co.,
trade name: TR-927). Test plate having higher OD values are judged
to have better surface smoothness and higher gloss.
[0133] Test pieces of Examples 1-8 were tested for transmission
rate and appearance and evaluation. The results are summarized in
the following Table I.
9 TABLE I Transmission rate ratio Example T.sub.A T.sub.B T.sub.C
OD Value 1 0.76 0.81 1.01 2.53 2 0.64 0.76 0.90 2.46 3 0.62 0.75
0.91 2.45 4 0.96 1.00 0.97 2.42 5 0.95 0.94 0.93 2.40 6 0.73 0.82
0.92 1.97 7 0.93 0.93 0.93 1.81 8 0.88 0.93 1.00 1.95
[0134] Examples 9-14 describe the black resin compositions for
laser absorption.
Example 9
[0135] The following formulation was used:
10 Nylon 6 400 g Carbon black (Product of Mitsubishi Kagaku Co.,
0.80 g Product name: #960)
[0136] In this Example and the following Examples 10-12, after the
tumbling operation, the mixture was melted and mixed at 250.degree.
C. and made into black pellets by cutting at a regular length (2-3
mm), with using a Bent type extruder (commercially available under
the product name E30SV from Enpler Industry Co.), and the pellets
were dried in a dryer at 80.degree. C. for 3 hours.
[0137] The pellet was then injection molded to form the injection
molded test specimens (whose sizes are 48 mm.times.86 mm.times.3
mm) using K50-C produced by Kawaguchi Steel K.K. and the cylinder
temperature was set to 250.degree. C. Mold temperature was
60.degree. C. Good and uniformly black appearance and surface gloss
without color shading of the specimens were observed.
Example 10
[0138] The following formulation was used:
11 Nylon 6 400 g Nigrosine type dye (Product of Orient Chemical
0.80 g Industries, LTD., Product name: Nigrosine base SAP)
Example 11
[0139] The following formulation was used:
12 Nylon 6 400 g Carbon black (Product of Mitsubishi Kagaku Co.,
0.60 g Product name: #960) Nigrosine type dye (Product of Orient
Chemical 0.20 g Industries, LTD., Product name: Nigrosine base
EX)
Example 12
[0140] The following formulation was used:
13 Nylon 6 400 g Carbon black (Product of Mitsubishi Kagaku Co.,
0.08 g Product name: #960) Nigrosine type dye (Product of Orient
Chemical 0.48 g Industries, LTD., Product name: Nigrosine base EX)
Aniline black (Product of Noma Kagaku Co., Product 0.24 g name:
Diamond black S)
Example 13
[0141] The following formulation was used:
14 PET 400 g Carbon black (Product of Mitsubishi Kagaku Co., 0.80 g
Product name: #960)
[0142] In this Example, after the tumbling operation, the mixture
was melted and mixed at 280.degree. C. and made into black pellets
by cutting at a regular length (2-3 mm), with using a Bent type
extruder (commercially available under the product name E30SV from
Enpler Industry Co.), and the pellets were dried in a dryer at
140.degree. C. for 3 hours.
[0143] The pellet was then injection molded to form the injection
molded test specimens (whose sizes are 48 mm.times.86 mm.times.3
mm) using K50-C produced by Kawaguchi Steel K.K. and the cylinder
temperature was set to 280.degree. C. Mold temperature was
60.degree. C. Good and uniformly black appearance and surface gloss
without color shading of the specimens were observed.
Example 14
[0144] The following formulation was used:
15 PBT 400 g Carbon black (Product of Mitsubishi Kagaku Co., 0.80 g
Product name: #960)
[0145] In this Example, after the tumbling operation, the mixture
was melted and mixed at 270.degree. C. and made into black pellets
by cutting at a regular length (2-3 mm), with using a Bent type
extruder (commercially available under the product name E30SV from
Enpler Industry Co.), and the pellets were dried in a dryer at
140.degree. C. for 3 hours.
[0146] The pellet was then injection molded to form the injection
molded test specimens (whose sizes are 48 mm.times.86 mm.times.3
mm) using K50-C produced by Kawaguchi Steel K.K. and the cylinder
temperature was set to 260.degree. C. Mold temperature was
60.degree. C. Good and uniformly black appearance and surface gloss
without color shading of the specimens were observed.
[0147] Test pieces of Examples 8-14 were tested for transmission
rate and appearance and evaluation. The results are summarized in
the following Table II.
16 TABLE II Transmission rate ratio Example T.sub.A T.sub.B T.sub.C
OD Value 9 1.02 *8.0E-4 *7.0E-4 2.32 10 0.11 *2.4E-3 *2.0E-2 2.36
11 0.37 *2.2E-4 *5.6E-3 2.40 12 0.31 *1.8E-4 *5.2E-3 2.43 13 0.91
*1.5E-4 *1.1E-4 1.91 14 1.00 *3.5E-4 *3.2E-4 2.20 *E:
exponential
[0148] Examples 15-23 describe the resin fabricated molded products
for laser welding.
[0149] Laser welding with YAG laser and diode laser was carried out
using the experimental resins aforementioned obtained. YAG laser
condition:
[0150] Nd:YAG laser (OlionS10, 1064 nm, continuous) was irradiated
with 4W output onto test piece with 3 mm diameter for 3 seconds.
Diode laser condition:
[0151] Diode laser (SDL-FD25, 820 nm, continuous) was irradiated
with 4W output onto test pieces with 3 mm diameter for 10
seconds.
[0152] As to laser weldability, in each of Examples 15 through 23,
two resin parts that are respectively transparent and opaque for
such laser beams and formed of the compositions indicated in the
following Table III being welded were judged by visual inspection
Welded test pieces were visually inspected and judged OK when
adhesion was formed and NG when the two test pieces were not
adhered and fell apart or when the surface of transparent part were
burnt and damaged.
[0153] The results are set forth in Table III.
17TABLE III Composition as Compositions as Black resin Black resin
composition for composition for Laser Examples laser transmission
laser absorption Laser weldability 15 Example 1 Example 9 YAG OK 16
Example 2 Example 11 YAG OK 17 Example 6 Example 13 YAG OK 18
Example 1 Example 9 Diode OK 19 Example 4 Example 9 Diode OK 20
Example 4 Example 11 Diode OK 21 Example 5 Example 10 Diode OK 22
Example 7 Example 13 Diode OK 23 Example 8 Example 14 Diode OK
Examples 24-28, 30-31, Comparative Example 29, 32-36
[0154] Unreinforced Nylon 66 (Zytel.RTM. 101, available from E. I.
DuPont de Nemours and Co.) and dyes and pigments were dry-blended
with the amount described on the table IV-1 and IV-2. The blended
material was molded into the test pieces for laser welding, with
dimension illustrated as FIG. 2A, using an injection molding
machine (K50-C, a product of Kawaguchi Tekko Co.) with cylinder
temperature set at 270.degree. C. and mold temperature set at
65.degree. C. Light transmittance at 940 nm was measured using 2-mm
thick area of this molded test plate using a spectrophotometer
(product of Hitachi Co., U-3410 model). Laser welding was conducted
using two pieces of the test pieces combined as illustrated in FIG.
2B. Each example from 24 to 28, comparative example 29, example
from 30 to 31, and comparative example from 32 to 35 was used as
the Lower test piece and Comparative Example 36 was used as the
Upper test piece. Diode laser (wavelength 940 nm, manufactured by
Rofin-Sinar Laser GmbH) was irradiated with laser power at 80W and
with speed at 1 m/min. Welded test pieces were visually inspected
and judged OK when uniform adhesion was formed across the test
piece, and judged NG, when the two test pieces were not adhered and
fell apart, when the adhesion was not formed uniformly across the
test piece, or when the surface of transparent part was burnt and
damaged
18 TABLE IV-1 Example 24 Example 25 Example 26 Example 27 Example
28 Comp. Ex. 29 Zytel .RTM.101 499.25 499.5 499.65 499.75 499.85
499.95 Carbon black 0.75 0.5 0.35 0.25 0.15 0.05 *Transmittance 0 0
*4.0E-4 *2.5E-3 *2.9E-2 0.22 Laser weldability OK OK OK OK OK NG
*transmission rate ratio (T.sub.black resin for laser
absorption/T.sub.natural resin) *E: exponential
[0155]
19 TABLE IV-2 Example 30 Example 31 Comp. Ex. 32 Comp. Ex. 33 Comp.
Ex. 34 Comp. Ex. 35 Comp. Ex. 36 Zytel .RTM.101 499.25 499.5 499.65
499.75 499.85 499.95 500 Nigrosine dye 0.75 0.5 0.35 0.25 0.15 0.05
0 *Transmittance 3.6E-2 0.10 0.21 0.28 0.49 0.72 -- Laser
weldability OK OK NG NG NG NG -- *transmission rate ratio
(T.sub.black resin for laser absorption/T.sub.natural resin) *E:
exponential
[0156] The Examples from 24 to 28, 30, and 31 which had
transmittance, as expressed as transmission rate ratio as defined
above, less than 0.20 exhibited laser weldability. But the
Comparative Examples 29, and from 32 to 35, which had transmittance
greater than 0.20 did not have laser weldability.
Examples 37-49, Comparative Example 50
[0157] Unreinforced Nylon 66 (Zytel.RTM. 103FHS, available from E.
I. DuPont de Nemours and Co.) and dyes and pigments were
dry-blended with the amount described on the table IV. The blended
material was molded into the test pieces for laser welding, with
dimension illustrated as FIG. 1A, using an injection molding
machine (Sumitomo Juki 75T) with cylinder temperature set at
270.degree. C. and mold temperature set at 65.degree. C. Laser
welding was conducted using two pieces of the test pieces combined
as illustrated in FIG. 1B. Each example from 37 to 49 was used as
the Lower test piece and Comparative Example 50 was used as the
Upper test piece. Diode laser (wavelength 940 nm, manufactured by
Rofin-Sinar Laser GmbH) was irradiated with laser power at 120W and
with various speeds. Tensile strength of the welded test pieces was
measured on Autograph (manufactured by Shimazu Seisakusho) by
pulling apart at 5 mm/minute and its maximum load was recorded. In
case Laser welding strength is more than 70, we consider that it
can use in industrial welding.
20 TABLE V Comp. Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam-
Exam- Exam- Exam- Exam- Exam- Ex. ple 37 ple 38 ple 39 ple 40 ple
41 ple 42 ple 43 ple 44 ple 45 ple 46 ple 47 ple 48 ple 49 50 Zytel
.RTM. 499.5 499.0 498.75 497.5 498.5 497.0 498.75 498.75 497.5
498.25 498.0 498.25 498.25 500 103FHS Carbon black 0.5 1.0 0.125
0.25 0.5 0.5 0.5 0.625 Nigrosine type 1.25 2.5 0.75 1.50 1.25 0.75
dye 1* (SAP) Nigrosine type 1.5 3.0 0.95 1.5 0.95 dye 2* (Cramity)
Aniline black 0.25 0.375 0.75 0.25 0.375 Phthalocyanine 0.05 0.05
black Laser welding Laser welding strength (kgf) speed 2.5 m/min 44
93 90 84 78 5 m/min 77 86 105 99 118 89 97 103 79 103 120 103 93 10
m/min 48 102 51 134 74 161 0 0 132 126 145 114 106 13 m/min 99 117
145 130 126 129 92 121 20 m/min 9 7 17 0 29 31 29 15 Nigrosine type
dye 1*: Nigrosine base SAP produced by Orient Chemical Industries,
Ltd. Nigrosine type dye 2*: Cramity 81 produced by Orient Chemical
Industries, Ltd.
* * * * *