LU80331A1 - COMPOSITE MATERIAL BASED ON METHYL POLYMETHACRYLATE - Google Patents

Description

. OC 50.128

-0 -0 3 — J pHAND-DUCHY OF LUXEMBOURG

Patent No ............................................... .....

from .. .6 ..... October ..... 1.9.7..8 .. Mr. Minister of 1¾0011011 ^ National and the Middle Classes

Title issued ......................................... Industrial Property Service

'löF LUXEMBOURG

Patent Application I. Application ........... The company. ... said. CHEMICALS ..... UGIM .... ™ ^ TOUR ................ (i) ........... M & NHATTAM .. .-..... IA ... DEEEÎÎSE ..... 2., ........... 6 ..... Elace ..... de ... ^ .. '.Ir.is .., ...... ll ..... 9.2.4C> Q ........................

s ........... Courbevoie. * France * Kepx.§sen.t ^ .e ..... p.ar..JÆQnsis.ur ..... "I.ac.g ! ô. © .s ..... de ...................... (2> .......... JSiuyser. * ..... acting ..... in ..... quality ..... of .... m.andafcair.e ................. .................................................. ..................

drop off ........ this ....... six ..... actobr.e ..... 13.oo..sQty .-. dix.-JbLuit ----- ------------------------------------------ (3) to .... ........... 15 ......... hours, at the Ministry of National Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a invention patent concerning: ............ ï! Material.au ..... cQiap.o.sit.e ...... a .... bass .., .d.ft ... pQ.l.ymâtb.acry.latê .... de „MthYlel, .... (4) declares, assuming responsibility for this declaration, that the inventor (s) is (are): ............ l ...- .. J & anr.Paul.QLLIVIER, ...... 5.2 ..... rue ... Letor.t *. .... à ... 75ol8 ..... PARIS .., ..... Erance (5) ............ 2. ^.-... Albert .. ..STRASSEL.f ..... 3 a * ..... ruePasteur * ...... at ..... 69 & oo ..... QULLIHS * ..... France., 2. the delegation of power, dated ...... COURBEVOIE ..................... the 2.9 ...... September ..... 19.78 3. description in language. ...... French ....................... .............. of the invention in two copies; 4 ...... 1 .................. drawing boards, in two copies; 5. the receipt of the taxes paid to the Luxembourg Registration Office on ............. 6 ...... October ..... 1978 ...... .................................................. .................................................. .................................................. ................................................

r ^ WdM · / kfckM ΗΦΝ ίΦΜ & ΙΦΗΦ-Ν kfebl (6) .................................... .................................................. .......... filed in (7) ................................ .................................................. ............................................

the ................................................. .................................................. .................................................. .................................................. ................... (8) on behalf of ......................... .................................................. .................................................. .............................. (9) elect domicile for him / her and, if designated, for his / her proxy, at Luxembourg ......................................- .......... ..3.5. * ..... bld ....... Royal ............................... .................................................. .................................................. .................................................. ................... (io) requests the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, - with adjournment of this grant at ________ 18______________________ _________months.

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Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of National Economy and the Middle Classes, Industrial Property Service in Luxembourg, dated: October 6, 1978 Π A / A at 3 p.m. / \ de l'Économie National and Middle Classes, f- J rv / i '/ ·. , "f: \ P · d.

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(5 S 4 »* A 6800V -------- · 'hr r __________________——-———— r— D. 50.128

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Brief Description filed in support of a request for

PATENT

at

Luxembourg l

formed by: CHEMICALS UGINE KUHLMANN

for: "Composite material based on polymethyl methacrylate".

'naked.

Here "- . - - '· - Ί' ““ "" “'•' Composite material I based on polymethyl methscrylate"

Inventors:

Jean-Paul DLLIVIER and Albert STRASSEL The present invention relates to a composite material, 5 consisting of a polymethyl methscrylate, commonly known as PMMA coated with polyvinylidene fluoride commonly known as PVF2 · This material has the advantage, unlike or polymethyl methacrylate, to have excellent resistance to aging and particularly to resist miPEO-'fissura- • j 0 tion, The invention also relates to the manufacturing process ·· to avoid micro-cracking of PMMA.

The PMMA surface micro-cracking phenomenon, although much studied, has not been avoided until the present invention. This phenomenon corresponds to the appearance of a number 15 of small surface cracks on the surface of PMMA during aging. These more or less deep cracks affect not only the surface appearance but also sometimes the mechanical resistance of PMMA. This phenomenon is mainly caused by humidity, solvents and certain CDrro-20 sive atmospheres when PMMA is under stress. This phenomenon which can even lead to the destruction of the PMMA part is sometimes due to internal tensions resulting from an inadequate transformation of the resin.

Due to this drawback, the use of PK.MA, which also poses excellent qualities of transparency, # resistance to ultraviolet light, transmission to X-rays and the like, is unsuitable for certain applications.

The composite material which is the subject of the invention while retaining the qualities of PMMA does not have the drawback of cracking on the surface.

This composite material is characterized in c-. that at least on a surface of a PMMA element is fixed a coating -, ‘- raent of

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4, _ __--—- - - .ι-m · PVF2, the maximum thickness of which is ten times less than the thickness of the PMMA element, without, however, the coating thickness being more than 400 microns and preferably greater than 1GG microns.

The PVF ^ coating is in the form of a film or a film prepared according to conventional methods, such as for example by extrusion or coating. For the manufacture of the coating, the resin of PVF 2 is suitable, it being understood that under this name are included the homopolymer and the copolymers containing at least 70% by weight of PVF 2. Although PV is generally used in its pure state, it is not excluded to incorporate fillers, pigments, plasticizers, stabilizers and other usual ingredients into it.

The PMMA element suitable for making the composite material is obtained by any known means such as, for example, by extrusion, injection, compression molding, centering molding: fugation and can be in the form of a sheet, plate, .tube or any object.

In order to preserve the maximum of the characteristics of the PMMA PO it is desirable to adhere the PVF2 to the PMMA by means of a bonding intermediate having the same optical properties as the PMMA. One of the means of producing this composite material is described in the request for French addition certificate n ° 77 / 00.327. This means consists in depositing on the surface to be fixed t5 of PVF2 a thin film of PMMA from a solution of PMMA in a polar aprotic solvent. The PVF9 is then heated to a temperature between 100 and 250 ° C for a few minutes so as to remove the solvent. After cooling, the treated surface of PVF2 is applied to the element of.PMMA, and: 0 the assembly is made to adhere by heat sealing,

The composite material which is the subject of the invention is particularly recommended for applications requiring good resistance to aging of PMMA, particularly in the medical and health fields as well as in the building industry.

The following examples illustrate the invention: /

'. % ED

yi r -----] ’EXAMPLE 1

One side of a 25 micron thick PVF ^ film obtained by extrusion blow molding is treated with a 10% by weight solution of polymethyl methacrylate of molecular weight approximately 120,000 in a 2/1 mixture by weight of dimethylformamide / ethyl acetate by coating with a doctor blade and pass the film thus "coated in an oven heated to 140 ° C. for 3 min.

The PVF2 film is applied to a ΡΗΜΑ plate (ALTUGLAS M70 from the company ALTUL0R) 3 mm thick in exer-1 (1 pressing a pressure of 38. kg / cm ^ respectively for 2 minutes, the plates of the Press being at 145 ° C., a obtient plate coated with perfectly adherent PVF2 is obtained. In the same way, a composite material is prepared from a ΡΗΜΑ plate 4 mm thick, the pressure exerted is 15 kg. / cm.

£ 1. EXAMPLE 2 -.

A 20% ί by weight solution of PVF ^ dry extract in dimethylforrnamide is applied using a doctor blade on a transfer paper which is passed continuously through an oven heated to 15 ° C. passage time is around 3 minutes. A PVF film is thus obtained: -30 microns thick. Using a second doctor blade, the PMMA solution in the dimethylformamide / ethyl acetate mixture of Example 1 is applied to the PVF2. The film is passed through a second oven for 3 minutes at 140 ° C. Then the treated PVF film ^ is peeled off from the transfer paper. Furthermore, a PMMA ("ALTULITE" from the

ALTUL0R) in the form of a plate 3 mm thick and the PVF2 film is unwound by applying the treated face of PVF ^ on the PMMA continuously at a temperature of 100 to 130 ° C by means of the line polishing train, 3 {j It can be seen that the plates of Examples 1 and 2 give the same results as regards the tests relating to the cracks which follow: The study of cracks is done by subjecting the test pieces to a bending stress and the propagation of the cracks is monitored visually. A stress setting diagram is given in the annex figure, the distance "F” representing /

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] -1 Γ ----— ’the arrow and” L ’’ the extent of the cracked area.

The 20 x 200 mm test pieces are subjected to static bending stress, the PVF ^ being on the convex face. The cracks propagate in the direction perpendicular to the largest of the stresses, and multiply in the direction of this stress.

In order to accelerate cracks, solvents such as chloroform, toluene and propanol are used. They are widespread in the place where the stress is maximum using a blotter 1 soaked in it 50 mm in length. The time it takes for cracks to appear and the extent of the cracked area as a function of time are measured.

_ Extent of

... cracked area L

Appearance arrow after. _ ___ cracks ^ minute 4 minutes Π H ~ “

PnMA alone Toluene 5 mm - 10 - 15 s 42 mm 46 mm

Propanol - 25 - 30 s 26 ram 35 mm

Instant chloroform 50 mm 70 mm

Examples Toluene; 1 and 2 Propanol 5 mm No cracks ’Chloroform L ·.

»T i r f i i

Claims (3)

1. Composite material based on polymethyl methacrylate having an excellent resistance to aging and particularly to micro-cracking characterized in that at least on a 5 ′ surface of an element in polymethyl methacrylate is fixed a polyvinylidene fluoride coating, the maximum thickness of which is ten times less than the thickness of the polymethyl methacrylate element without, however, the thickness of the coating being greater than 400 microns. 10 2 - Manufacturing process making it possible to improve the resistance to aging and particularly to micro-cracking of a polymethyl methacrylate element, characterized in that at least on a surface of the element in polymethyl methacrylate, a coating is fixed of polyvinylidene fluoride, the maximum thickness of which is ten times less than the thickness of the polymethyl methacrylate material without, however, the thickness of the coating being greater than 400 microns. 3. Method according to claim 2 characterized in that the po-x vinylidene lyfluoride is fixed on the polymethyl methacrylate by means of a bonding intermediate having the same optical properties as polymethyl methacrylate. 'υοΟΟΟλ) V