Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2000-09-01
2002-02-19
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S186000, C522S184000, C522S150000, C522S155000, C522S147000, C522S146000, C522S102000, C522S103000, C522S071000, C522S075000, C522S076000, C522S077000, C522S078000, C522S079000, C522S080000, C522S081000, C522S082000, C522S083000, C525S416000, C524S568000, C524S569000, C526S344000, C526S344300, C526S081000
Reexamination Certificate
active
06348517
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the preparation of a sterile article made from a polymer having a halogen-containing repeating unit, where the polymer contains a compound based on a poly(oxyalkylene) (POA). In particular, it relates reducing the yellowing of an article made from polyvinyl chloride (PVC) after exposure to gamma radiation by incorporating compounds based on poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) into the PVC.
PVC is a versatile thermoplastic that is widely used for making medical articles and for food packaging due to its clarity, gloss, unique versatility, excellent functional performance, inertness to fluids, and relatively low cost. Medical devices and food packaging are usually sterilized before they are used. While ethylene oxide sterilization imposes little or no harmful effects on the physical properties of PVC, radiation sterilization, such as with gamma rays, can adversely effect the polymer, such as yellowing it.
PEG, PEG dibenzoate, and PPG dibenzoate have been used as PVC plasticizers. They are primarily used as alternatives for phthlate plasticizers, such as dioctyl phthalate (DOP). The use of these materials may also improve other properties of PVC. (J. H. Lee, K. O. Kim, Y. M. Ju J. Biomed. Mater. Res (Appl. Biomater) 48, pages 328 to 334 (1999); W. D. Arendt, J. Lang J. Vinyl & Additive Technology, 4(3), pages 184 to 188 (1998); W. D. Arendt Plast. Eng. 35(9), pages 46 to 49 (1979); W. D. Arendt Plast. Eng. 25, pages 410 to 412 (1979).
SUMMARY OF THE INVENTION
We have discovered that POA-based compounds inhibit the yellowing of polymers having halogen-containing repeating units after exposure to sterilizing radiation. The stabilizers of this invention also improve the mechanical strength of PVC compounds and reduce or eliminate the need to use DOP.
Some of the stabilizers of this invention are novel compounds while others are commercially available.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The stabilizers of this invention have the general formula: TGOT′, where each T is independently selected from R—, R—CO—, —P(R)
2
, —P(OR)
2
, —Si(R)
3
, or —Si(OR)
3
, T′ is T or A[GOT]
n
, each A is independently selected from LS—Sn(R)
3
−
q
(SLJ)
q
, L—O—Sn(R)
−q
(OLJ)
q
, (CH
2
)
p
S—Sn(R)
3−q
(S(CH
2
)
p
—J)
q
, LCO
2
Sn(R)
3−q
(OLCO—J)
q
, or LSn(Y)
3−q
(LJ)
q
when n is 0, from CO, E, CO—E—CO, Si(R)
2
, Si(OR)
2
, (Si(R)
2
G)
r
, (CO—E—CO—G)
r
, (CO—G)
r
, or (E—G)
r
when n is 1, and from P, PO, and trimellitate when n is 2, Y is —SLJ, —SLOR, —OLJ, —OLR, —S(CH
2
)
p
—J, —S(CH
2
)
p
R, OLCO—J, or OLCOOR, G is (O—CH
2
—R′CH)
m
, J is O—(CH
2
CR′HO)T, L is CO(CH
2
)
p
, each R is independently selected from R′, aralkyl from C
6
to C
12
, and alkaryl from C
6
to C
12
, each R′ is independently selected from hydrogen, alkyl from C
1
to C
12
, and aryl from C
6
to C
12
, E is alkylene from C
1
to C
12
, aralkylene from C
6
to C
12
, alkarylene from C
6
to C
12
, arylene from C
6
to C
12
, m is 1 to 20, n is 0 to 2, p is 0 to 10, q is 0 to 3, and r is 1 to 20. The ethers (T=R, T′=R) are preferred and R is preferably alkyl from C
1
to C
8
as those stabilizers are more effective, R′ is preferably methyl or phenyl because they increase the lipophilicity of the stabilizers, resulting in better miscibility with the polymers. The A group is preferably CO—E—CO or (CO—E—CO—G)
r
because the lipophilicity of the materials can be tailored and these materials are easily prepared. The Y group is preferably —SLJ, —SLOR, —S(CH
2
)
p
—J, or —S(CH
2
)
p
R because they are more effective. Of the tin stabilizers, sulfer-containing tin stabilizers are preferred, because they are better thermo stabilizers. Finally, m is preferably 2 to 5 as smaller values may be less effective and greater values may not be compatible with PVC, resulting in a hazy appearance, n is preferably 0 to 1 because these stabilizers can better inhibit the discoloration of the polymers, p is preferably 1 to 2 because these stabilizers are readily available, q is preferably 1 to 2 because those stabilizers are also better thermal stabilizers, and r is preferably 2 to 5 because they mix well with PVC. Preferably, all the T groups are identical as those stabilizers are easier to prepare.
The general formula includes PEG and PPG ethers: R—G —OR, PEG and PPG esters: R—CO—G—OCO—R, tin compounds: (R)
q
Sn—(MR″—G—OT)
4−q
, silicates: (R)
3
—Si—G—Si(R)
3
, phosphites: P—(GOT)
3
, phosphates: OP—(GOT)
3
, phthalates:
and trimellitates:
where M is O or S (and is preferably S) and R″ is (CH
2
)
p
CO—, CO—(CH
3
)
p
CO—, —(CH
2
)
p
, or —CO(CH
2
)
p
— (and is preferably (CH
2
)
p
CO—).
Examples of PEG, PPG, and their ethers and esters include tri(propylene glycol), poly(propylene glycol), poly(propylene glycol)diglycidyl ether, dibutoxypropoxypropyl adipate, poly(propylene glycol di(2-ethylhexanoate), poly(propylene glycol) dibenzoate, di(propylene glycol) dibenzoate, poly(ethylene glycol) dibenzoate, and di(ethylene glycol) dibenzoate. Examples of tin compounds include dibutyltin bis(diethylene glycol monomethyl ether thioglycolate), dibutyltin bis(triethylene glycol monomethyl ether thioglycolate), dibutyltin bis(diethylene glycol monoethyl ether thioglycolate), dibutyltin bis(triethylene glycol monoethyl ether thioglycolate), dibutyltin bis(dipropylene glycol monoethyl ether thioglycolate), dibutyltin bis(tripropylene glycol monoethyl ether thioglycolate), bis(&bgr;-carbomethoxyethoxyethoxy)tin bis(isooctylthioglycoate), bis(&bgr;-carboethoxyethoxyethoxy)tin bis(isooctylthioglycoate), and bis(&bgr;-carboethoxyethoxyethoxyethoxy)tin bis(isooctylthioglycoate). Examples of silicates include poly(propylene glycol) bistrimethylsily ether, poly(propylene glycol) bistrimethoxysily ether, poly(ethylene glycol) bistrimethylsily ether, and poly(ethylene glycol) bistrimethoxysily ether. Examples of phosphites include tri(methoxyethoxyethyl) phosphite, tri(ethoxyethoxyethyl) phosphite, tri(methoxypropoxypropyl) phosphite, tri(ethoxypropoxypropyl) phosphite, tri(methoxyethoxyethoxyethyl) phosphite, tri(ethoxyethoxyethoxyethyl) phosphite, tri(methoxypropoxypropbxypropyl) phosphite, and tri(ethoxypropoxypropoxypropyl) phosphite. Examples of phosphates include tri(methoxypropoxypropyl) phosphate, tri(ethoxypropoxypropyl) phosphate, tri(methoxyethoxyethoxyethyl) phosphate, tri(ethoxyethoxyethoxyethyl) phosphate, tri(methoxypropoxypropoxypropyl) phosphate, and tri(ethoxypropoxypropoxypropyl) phosphate. Examples of phthalates include di(diethylene glycol monomethyl ether) phthalate, di(triethylene glycol monomethyl ether) phthalate, di(diethylene glycol monoethyl ether) phthalate, di(triethylene glycol monoethyl ether) phthalate, di(dipropylene glycol monoethyl ether) phthalate, and di(tripropylene glycol monoethyl ether) phthalate. Examples of trimellitates include tri(diethylene glycol monomethyl ether) trimellitate, di(triethylene glycol monomethyl ether) trimellitate, di(diethylene glycol monoethyl ether) trimellitate, di(triethylene glycol monoethyl ether) trimellitate, di(dipropylene glycol monoethyl ether) trimellitate, and di(tripropylene glycol monoethyl ether) trimellitate. The preferred stabilizers are ethers and esters of PEG and PPG because many are commercially available.
Polyethylene glycol and polypropylene glycol ethers and esters that are not commercially available are easily made by, for example, condensing polyethylene glycol or polypropylene glycol with an alcohol (to make an ether) or with an acid chloride (to make an ester), as is well-known in the art. Of the above compounds, the PEG and PPG ethers, silyl ethers, and esters are well known. Phthalates such as dimethyl glycol phthalate, diethyl glycol phthalate, dibutyl glycol phthalate; di-2-(2-methoxyethoxy)ethyl phthalate; di-2-(2-ethoxyethoxy)ethyl phthalate; di-2-(2-butoxyethoxy)ethyl phthalate; di-2-(2-hexyloxyethoxy)ethyl phthalate; bis[2-[2-(2-ethoxyethoxy)ethoxy]ethyl&
Nagy Sandor
Wang Qi
Fuerle Richard D.
McClendon Sanza L.
Oxy Services, Inc.
Seidleck James J.
LandOfFree
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