JPH01500128A - Temperature indicators based on polydiacetylene compounds - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Temperature indicators based on polydiacetylene compounds The present invention is based on polydiacetylene compounds. Concerning material-based temperature indicators.

Temperature history of perishable products, especially temperatures that may reduce the quality of the product in question It is necessary to know whether the threshold has been crossed. This is for example food, medicine, photographic products Or biomedicine. In particular, the application of frozen or quick-frozen products has recently become popular. In terms of A method is needed.

The present invention is characterized by the irreversible color change during temperature rise of thin films of diacetylene polymers. How to detect if the temperature threshold of a perishable product has been exceeded using the principle of I will provide a.

Acetylene compounds have been studied for a long time since the 1950s, especially for their photosensitive properties. It's here.

Certain diacetylenes are generally produced in the solid state by thermal effects or by high-energy irradiation ( It has the property of polymerizing through exposure to UV (UV, X-rays or gamma rays, slow electrons).

Polymerization occurs at the 1.4 position with the following scheme.

The monomers are generally colorless but absorb strongly in the UV region. A strong color appears during polymerization It will be done. Generally, this coloration occurs along the polymer chain through the overlap of the carbon pi orbitals. It has been understood that this is due to the strong delocalization of pi electrons.

It is possible to establish a relationship between the color of the polymer and the conjugation length. blue in nickel acid is known to appear when the polydiacetylene chain is planar and rigid. Ru. The conjugation length is greater than about 30 monomer units. If the chain is partially planar or regular The polymer turns red when it is blocked, that is, when the conjugation length decreases.

Symmetrical C6, C8, and C12 alkyl diacetylenes i.e. hexa -2,4-diyne, octa-3,5-diyne, and dodeca-5,7-diyne are , manufactured by Arlltage et al. for the purpose of studying their spectroscopic properties. [J, Cherr, Soc, 44 (1951) and 19 98 (1952)]. BAUGHMAN et al. [J, Pol, Sei.

Po1. Phys, Ed, 11. 609 (1973)] was followed by , states that this polymer can be polymerized only with great difficulty.

The main asymmetric diacetylenic hydrocarbons that have been studied are derivatives of the following formula:

H-CIC-CIC-R In the formula, R-CHn is 2 or 4.

n 2n+11 To the knowledge of the applicant's country, there is only one unpaired compound with a long paraffinic side chain. The term hydrocarbon, namely hexacosa-11°13-diyne, is found in the literature (FrenchPa. tent 1525 738).

Diacetylenic diacids in a crystalline state quickly develop a color, generally red, when exposed to light. The chain For example, when carbon atoms are 22, the same diacid takes on a blue color upon irradiation; It turns red when heated.

The existence of color changes in diacetylene derivatives in general has therefore been known for a long time.

French Patent No. 1 525 738 discloses photosensitive diacetylene that can be used for image recording. It describes a long series of These diacetylenes are primarily 10 ．． diacids containing 20, and 24 carbons, the corresponding esters, and 24 and 28 It is an alkyl diacetylene of carbon atoms. The patent describes the color and The color change from blue to red at approximately 20-25°C, which describes the sensitivity to radiation, is The case of tracosar-11°13 diyne is described. Heated or irradiated heavy Upon contact with the solvent for coalescence, the perturbation of the crystal structure (pertubatlon) , causing a transition or change from the original photosensitive product to other red colored products. this red Products exhibit thermochroic and irreversible color changes.

French patent 2 341 848 is based on diacetylene or polyacetylene derivatives. Regarding the time and temperature history indicator used by the body. The principle is the polymerization of diacetylene It is based on the color change of the sample during the test. The rate of polymerization depends on the temperature of the sample. time A one-temperature integrator is obtained. The monomers used are diacetate from the following set: is a urethane, sulfonate, asymmetric acid-alcohol molecule, or the formula Cyclic derivatives corresponding to: In addition, we particularly investigated the reactivity of diacetylene. Substitution with paraffinic chains The reactivity of diacetylenes is determined by the evenness of the number of carbons forming this chain (eνen nes). The highest reactivity is obtained with side chains with an equal number of carbons. Ru.

Wegner also studied the reactivity of these molecules as a function of wavelength, and he The highest sensitivity was obtained for UV wavelengths around nm. This is due to the conjugated triple bond and the Corresponds to absorption of both kill chains.

European Patent No. 0 036 899 describes a reversible thermochromic system for temperature measurement. The present invention relates to a polymerizable diacetylene composition. The proposed diacetylene has the following formula It is a derivative of: R-NHOCo (CH2) C! ! ICC! =IC(CH2 )　OCo　NHR’n　n where n-2, 3 or 4, and R and R' are especially 01-04 alkyl groups. be.

These systems exhibit a thermochromic histology that can vary from a few degrees to 80 °C. Showing telesis. This hysteresis is used for polymerization by administration of gamma irradiation. It is possible to relate to Two weak doses form the highest hysteresis effect However, strong doses of irradiation form a high degree of transformation into polymers, and This produces a small hysteresis effect.

In recent literature, J. KIJI et al. [Chem, Lett.

Jp, 35.1985] Ei, 16. with 20, 24 and 28 carbon atoms A series of symmetrical alkyl diacetylenes was re-investigated. Polymerization was carried out by UV irradiation at -78°C. was achieved by giving a red polymer. Thermochromic properties for these polymers There is no description of the rhythm.

The above prior art shows that polydiacetylene compounds are indeed widely used with respect to their photosensitivity. It shows that it has been studied. However, depending on various parameters, The color changes observed in different polymers are not always irreversible. is attracting attention.

A diaphragm that polymerizes to form a polymer that undergoes an irreversible color change from blue to red at a given temperature. A series of cetylenic monomers has been discovered.

Suitable monomers for obtaining the temperature indicator according to the invention have the general formula R-C==C-C It is diacetylene of MiC-R. In the formula, the substituent R is a saturated aliphatic chain. They are It can be represented by the following formula I.

CH3-(CH2)-CIC-C! ! IC-(CH2) --CH3 (1) formula where n and n' are the same or different and represent an integer from 2 to 21; unpaired compounds (where n and n' are different) are particularly preferred for the purposes of the present invention.

For convenience, in the following explanation, the above diacetylene will be referred to as the total number of carbon atoms in the monomer unit. It is shown by. For example, C16, C20% C22, C24, C2B, and C It is 32. Additionally, for asymmetric diacetylene monomers, the raw material monoacetylene The number of carbons in the carbon compound is added as a subscript.

For example, C15(sto) represents octadeca-7,9-diyne, and C22(sto) represents octadeca-7,9-diyne. 814) represents dococer-7,9-diyne. These diacetylene monomers are All are colorless.

The above monomer or mixture thereof can be used in a crystalline film (crystalline flIn). Or it can be polymerized only in the crystalline state in the form of a single crystal. The crystalline state changes from the liquid state or by crystallization from solution.

Polymerization can be carried out in different ways known to those skilled in the art.

In particular, possible methods include high-energy irradiation, such as UV irradiation, X-rays or gamma rays. , or photopolymerization by exposure to slow electron radiation. Polymerization depends on temperature and crystallization It depends on the structure and varies depending on the substrate on which the monomer is placed.

The resulting polymer or polymer/monomer mixture is blue in color.

These have varying widths for long wavelengths in the visible spectrum (580-650 nm). It has an absorption band. These bands change to a slightly shorter wavelength when the polymerization time is increased. It is noted that there is a tendency to shift to

The blue color is already evident at low degrees of polymerization (of the order of 1 percent). In the following explanation , “The term polydiacetylene compound° refers to all blue-colored products, Represents a pure polymer or a mixture of polymers/monomers, even if the proportions are low .

While increasing the temperature of the resulting polydiacetylenic compound, the polydiacetylenic chains Melting of the side chains provides mobility to the chains. This is the plane of the chain This results in a loss of stability, that is, a decrease in conjugate length. This is due to the large absorption spectrum. This becomes clear through changes. The absorption band at 600-650 nm tends to disappear. Ru.

This thermodynamic transition (tran) induces a color change in polydiacetylene compounds. slstion) corresponds to the fusion of the alkyl chains of the polymer. It has been shown that. Furthermore, the order of the actual polymerization system (or This color change or transition, which is equivalent to a decrease in der), is irreversible.

Therefore, the special thermochromic properties, i.e. the length of the alkyl chains of the raw monomers polydiacetile exhibiting an irreversible color change from blue to red that occurs at a given temperature characteristic of A new series has been selected. These polydiacetylene compounds are temperature indicators (temperature 1ndicators) Ru.

Therefore, the present invention relates to the diacetylenic monomer of formula (I) defined above or its consisting of at least one polydiacetylene compound obtained by polymerization of the mixture related to temperature indicators. Here, the monomer is in a crystalline state.

It must be inert not only against cetylenic compounds, but also against putrefying products. Must be. e.g. paper, glass, textiles, quartz, metals e.g. aluminium, or Polymers such as polyethylene.

The temperature indicator of the present invention is a thermal indicator that is chemically inert to the polydiacetylene compound. Can be effectively mixed into plastics as additives or as mixtures. can.

Thermoplastics are those that are compatible with olefins, such as polyolefins. For example, it can be polyethylene. Mixing is carried out in the polymer in the molten state. The thin film obtained by coating and subsequent cooling forms a polydiacetylene compound. It is subjected to photopolymerization in order to

The temperature indicator can be a single polydiacetylene compound or a It can consist of a deeply selected mixture of such compounds.

The symmetrical diacetylenic monomer of the above formula (1) is described in the literature (EGL INGTON e tal, in J, CheIIl, Soc, 889 (1959)) by oxidative coupling of alkynes with copper salts according to the method described in can be obtained. This method uses pyridine/meth in the presence of copper salts such as copper acetate. Gentle pure oxygen in a nol/ether mixture at a temperature between about 30 and 35°C The process involves heating the alkyne under a stream of water for about 48 to 72 hours. ether and After removal of excess oxygen, methanol is removed, for example by evaporation under reduced pressure.

The solution was heated with fresh anhydrous pyridine at reflux between 40 and 50°C for 48 to 72 hours. processed below. The pyridine is then removed and the remaining mixture is acidified . After ether extraction, an oily product is obtained, which crystallizes on cooling. this The oily acid is then purified by chromatography using known methods.

As an example of raw alkynes, commercially available products without further purification Can be used. For example, the product name sold by EGA-ALDRICH is EGA 24,44. 2-2 (hexy-1-yne), EGA 24,446-5 (offchy 1-yne) In), EGA 24,438-4 (Dizzy 1-in), and EGA 2 4,440-6 (Dobcy 1-Inn). These products are It can also be synthesized. For example, C16 alkyne is sodium in liquid ammonia. It can be synthesized via muacetilide. This is followed by literature (W.

Zlegenbeln et al, Chea+1stry of Ac etylene, H,G.

Viehe, p. 187. Marcel Dekker NY (1969) Tetradecyl bromine in dimethylformamide according to the method described in Replaced by Mide.

Methods involving dehydrobromination of the corresponding 1,2-dibromide can also be used. . This method is known to those skilled in the art.

The asymmetric diacetylene monomer of formula (I) above has two types of monomers with different carbon chain lengths. acid by the method described above using a mixture of noacetylenic hydrocarbons in appropriate proportions. It can also be obtained by chemical coupling.

Polymerization of diacetylenic monomers of formula (I) involves forming thin crystals of monomers or monomer mixtures. Irradiation of the crystal film with high-energy radiation, such as UV radiation (254 nm UV lamp) This can be done more effectively.

The absorption properties of the polydiacetylene compounds formed vary with the polymerization time. ratio In a relatively short period of time (approximately 30 seconds), the resulting polydiacetylene compound The main absorption peak is shown at m. As the irradiation time increases, the spectrum shifts to shorter wavelengths However, the predominant color of the product remains blue.

All polydiacetylene compounds obtained after different irradiation times are considered for the purpose of the present invention. Although suitable, it has a relatively low degree of polymerization, that is, it has an absorption peak at about 580 to 650 nm. Preferably, polydiacetylene compounds are used.

A polydiacetylene compound obtained by irradiation of a single diacetylene monomer is Without any change in the degree of polymerization (vlthout wodlfification), a narrow temperature range It exhibits rapid color changes in the degree range. As mentioned above, the transition temperature depends on the number of carbons in the paraffin chain. Depends on. For symmetrical alkyl diacetylenes, the transition is C16, C20%C24 , C28, and C32 are separated by about 20 degrees. Mixing monomers with different alkyl chain lengths The polymer obtained by irradiation of the compound retains the color changing properties of the homopolymer, but , the transition range is generally between the temperatures of each monomer, by a pseudo-continuous range. (quasf-conttnous range) Exchange of individual ranges of transition temperatures ( (replace the discrete range). Mixed It is noted that the compounds generally have eutectics.

Furthermore, the monomers present in polydiacetylene compounds can be irradiated in a crystalline state. It is noted that it can be polymerized by The absorption spectrum obtained is This superposed on the reversible red spectrum In this case, the color indicators of the invention must be protected from polymerization-initiating radiation by any suitable method. No.

The invention is illustrated in more detail by the following non-limiting examples.

In these examples, monomer purity can be determined by gas chromatography, mass spectroscopy, , and checked by NMR.

The main residual impurity detected was the raw material alkyne, the concentration of which in each case was 2. % or less.

Production of tetracosal-11,13-diyne or C24 monomer (Formula 1:n-n'　9) Dobcy 1-in (EGA 24,440-6) (1.2 g) is copper acetate (4 g) Pyridine (100 cm'), methanol (300 cm3) and 72 hours in a mixture of tel (400 cm3) at 30-32 °C, in a gentle atmosphere of pure oxygen. heated under a stream of water. In the presence of 1 g of CuCl, excess dissolved oxygen After being removed by passage through Rougone, the ether and methanol are evaporated under reduced pressure. It was. The solution was quenched with fresh anhydrous pyridine (400 cm3) for 72 hours at 47°C (reflux). processed by the flow). Part of the pyridine is evaporated under reduced pressure, then the mixture is Acidified with 0% MCI aqueous solution. After ether extraction and evaporation, an oily liquid obtained, which crystallized after cooling. The oil was chromatographed on CHC13 on SiO□. Ruffed to give a clear oil at room temperature (0.877g, y-73%).

The product was analyzed by NMR, gas chromatography (97% purity), and mass spectrometry. (Peak 330).

By repeating the method of Example 1, C12, C16, C10%C22, C28, and C32 diacetylenes were obtained from the following alkynes: hexy-1-yne, ofthi -1-in, Sony 1-in, Digi 1-in, Undecy 1-in, Tetrazo C 1-in, and hexadedi 1-in. Differential scanning of these diacetylenes Micro calorimetry (differential scanning microc) Melting point (or transition temperature) measured by alorlmetry-, DSC) are shown in Table 1 below.

Table 1 Diacetylene n-n' M, p, 'C name C16 (as) 5-29 ．． 4 (a) Hexadeca-7,9-C: /C18 (99) 6 +8. 2 (b) Octadeca-8,10-diyne C20 (10to) 7-1.5 (a ) Eicosa-9,11-diyne C22 (,1-0l) 8 +31.1 (a ) F Kosa 10,12-Diyne DSC: (a) Speed 1.25℃m1n-” ( b) Speed 5.0℃m1n-' Example 3 Production of C16C20, C20C24, and C16-C28 monomer mixtures The monomers obtained according to Example 1 or 2 were mixed in liquid state. of these mixtures Transition temperatures were determined by differential scanning microcalorimetry (DSC). these The transition temperature diagrams of the mixtures are shown in the accompanying Figures 1a, 1b and 1c.

Here, the cellulose temperature is plotted on the vertical axis and the composition of the monomer mixture is plotted on the horizontal axis. There is. The scanning rate of the microcalorimeter was 5°C/min.

Figures 1a, 1b and 1c each show a mixture of: C16C20 Figure 1a C20C24 Figure 1b C26C28 Figure 1C 18% C20 and C20 for C26C20 and C20C24 mixtures, respectively. A eutectic was observed for 21% C24. The transition temperatures of these eutectics are each It was on the order of 30°C and -2°C.

Off-chi-1-yne and digi-1-yne are oxidized according to the method described above (Example 1). attached to the target coupling. The reaction gave a mixture of three monomers. Raw material Al By careful selection of the proportions of kin, a mixture formed essentially of two components can be obtained. I was able to

A mixture of 1.65 g of offchi 1-yne and 4.14 g desi 1-yne is 4% hexadeca-7,9-diyne, 33% octadeca-7,9-diyne, and 63% eicosa-9,11 diyne.

The transition temperature of this mixture is shown in Table 2. (Mixture number 1) The components of the mixture are separated by preparative chromatography. This separation was divided into three fractions (stationary phase SiO□-08, effluent acetate Nitrile). Gas chromatographic analysis of the useful fractions gives the following composition: Ta. : C15 (alo) 95%, C20 (10-1o) 2%, C16 (8-8) 1°5%. Mass spectral analysis shows that M-246 (NH3 chemical ionization, observed peaks: M+1, M+18) are octadeca-7,9-diyne (Ctg(s) 10)).

Transition temperatures were measured by differential scanning microcalorimetry (DSC). Transfer is -26 , a single peak located at 5°C occurred.

A mixture of numbers 2, 3, 4 and 5 consisting of two or three different diacetylenes is It was obtained according to the method of Example 4, 1 using the following set of alkynes. :pliers -1-in/tetrazocy 1-in, desi 1-in/dodecy 1-in, off Qi 1-yne/Tetrazocy 1-yne, and Desi 1-yne/Tetrazocy 1- in. The characteristics of these mixtures are shown in Table ①.

Asymmetric diacetylene fractions were obtained from these mixtures for use in Cl8(8-10). was isolated in a similar manner. Monomer purity checked by gas chromatography The degrees are as follows: Cl9 (514) 87% to C22 (1012) 96%.C 22 (814) 92% and C24 (10″-14) 96%. The transition temperature of tyrene is shown in Table ①.

The above mixture can be used for polymerization etc. without separation.

Table ■ I C1s (s 10) 10% C16 (8 g) -4043% C18 (8- 1o) -33 47%C20 (1010) -10 2C1e (s 14) 46%C19 (514) -28,115%C28 ( 1414) +27.63 C22 (1012) 21% C20 (10to) 19.5. -7.249%C22 (1012) -3,3 29%C24 (1212) +2.8 4 C22 (s 14) 68% C16 (8 g) -39,630% C22 (8 14) -21,4 5C24 (101-1) 3696C20 (10to) -1053%C24 ( 1014) +3.5 8%C28 (1414) +8.9 *(GC-FID) - Gas chromatography - Flame ionization detector di Acetylene n n' Melting point °C Name C1s C3to) 5 7 -2 6.5 Okdekar 7,9-diyne C19 (514) 2 11 -8.1 Nadeka-4,6-diyne C22 (1012) 7 9 + 3.1 Docosa-9 , 11-Diyne C22 (814) 5 11 +2.0 Tocosurf, 9-Diyne C24 (1014) 7 11 +18.2 Tetracosal-9,11-diyne B-Production of polydiacetylene compound The monomers or monomer mixtures obtained according to Examples 1 to 4 above are nm low power UV lamp (flux 15cm2 260μW/cm2) was subjected to photopolymerization. The monomer was in a crystalline state in the form of a thin film.

Polymerizability was determined on a sample of pure diacetylene. Most photochemically reactive pure Pure diacetylene (f’ool)% eicosa 9-11-diyne, C20(1 0-1o), Tetracosal-11,13-diyne, C24(1212), Docosa- 9°11-diyne, C22(1012) and tetracosal-9-11-diyne, It was C24 (1014). In Table ■, the most photochemically reactive dia Setylene mixtures (symmetrical + asymmetrical) are mixtures 1, 3. and 5.

The absorption spectrum of a polydiacetylene compound is determined by the fact that it has been crystallized in the form of a thin film. were recorded as a function of irradiation time for monomer samples.

These spectra are shown in Figures 2a, 2b, and 2c. child These represent polydiacetylene compounds obtained from the following monomers, respectively.

C20 (10to) (Figure 2a) and C24 (1212) (Figure 2b) C16(88)/C20(10to) blend containing 80% C20(1010) Compound (Fig. 2C) The legend for Fig. 2a, Fig. 2, and Fig. 2C is as follows: shown in the table; the times shown in this table correspond to the temperatures given in the column “Compound”. This is the photopolymerization time at

Table ■ Drawing Composite Line 0 Line 1 Line 2 Line 30I4Fig, 2a Eicosa-9 , 11-diyne monomer 30 seconds 35 minutes ---20℃ Pig, 2b Tetracosal-11,13-diyne-monomer 2 minutes 10 minutes 50 minutes 5℃ 30 seconds The obtained results show that the polydiacetylene compound is transparent in the near IR from 750 nm. It shows that it is clear. These compounds have a blue tint, which occurs during polymerization. It is noted that the shorter the interval, the clearer the image becomes.

The transition temperatures of the monomer and blue polymer were determined by differential scanning calorimetry to C24 (121 2) was measured. The results obtained are shown in Figure 3a (C24(1212) dia cetylene compound or D24DA), and Figure 3b (C24(12-1□) point lydiacetylene compound or C24PDA), and there is a similarity between the two melting diagrams. It has been shown that there is.

Different transmission spectra were recorded successively with increasing temperature. The polymer gradually turns blue I saw it change from to red. The polymer behaves similarly in all cases and has this color Change was always irreversible.

For example, in the method (by way of exaIIlple), FIG. 4a, Figures 4b' and 4C are from the C20 diacetylene monomer in Example 5. (Fig. 4a) or from the Cxc (a 8)/C2° (1o-1o) mixture (Fig. 4b and 4c) Absorption spectrum of the produced polydiacetylene compound , as a function of increasing temperature (solid line, -9°C to +3.5°C for C20, and -40°C to -2°C for C16(a8)/C20(lo to) mixture) Show change.

Returning to a lower temperature after melting gave the compound a red type absorption spectrum ( Discontinuous line, T--24℃ for C20, C16(88)/C20(10-1o) is T--23°C). Irreversibility was thus demonstrated.

Furthermore, the observed color change was persistent. In fact, in the exam, different types of Red C24 (1212) or C20 (10- 1o) The polymer retains three blades at a temperature of approximately -20°C without significant color change. Ta.

Thermochromism was observed for mixtures Nos. 1, 3 and 5 in Table 1. observation were performed using a thermal microscopy analyzer; monomers or mixtures were placed in a sapphire dish. This allowed UV polymerization and microscopic observation.

The mixture] was polymerized at -45° C. (UV 254 nm, 5 cm) for 10 minutes. color is blue -It is mauve in color. The onset of metastasis was seen at -15°C, turning dark red. This turn The transition was extended to -9°C when it became orange-red.

Mixture 3 was polymerized at -25° C. (UV 254 nm, 5 cm) for 5 minutes. The color is thick It is a very dark blue to black color. The transition started at -7°C when the polymer turned dark red. . It turned orange-red at -4°C and the transition was complete at +2°C.

Mixture 5 was polymerized at -20° C. (UV 254 nm, 5 cm) for 1 minute. The color is neutral It is blue and shiny. The transition started at about -8°C when the color became mauve. -3 The transition was completed at +5°C with an orange-red color.

Table 1V It is a photopolymerizable pure diacetylene. UV irradiation at 254 nm and a distance of 5 cm. Ru. ; (+++) Dark blue after 1 minute of opening during irradiation, C++) t,, Dark blue after 5 minutes, (+) Blue when t, r > 5 minutes, (-) tl, no polymerization after > 30 minutes.

Diacetylene Sample temperature ℃ Photopolymerizable C20 (1010) -20 (+++) C22 (1012) -15 (+++) aC22 (11xx) Room temperature (-) 028 (□4 14) Room temperature (+++), (-) (a) mauve ); (b) Two substrates, 5i02 chromatography plate, Rapid polymerization; (C) Polymerization without reproducibility; t, -irradiation time.

r Example 8: Preparation of polydiacetylene in polymer 2.5 mg of C24 (1212 ) The monomeric diacetylene was added to 2.7 mg of molten polyethylene (molecular weight 2 1.000). Cooling results in a thin film, which is then applied to the mixed diluted A temperature of +5° C. was applied to crystallize the acetylene.

The protective film was then subjected to 254 nm UV irradiation for 3 minutes. The membrane turned a deep blue.

Heating of the membrane was observed in a thermal microscope device from 5 to 25°C with a heating rate of 2°C per minute. Is it blue? The color change to rufous-colored begins at 12°C, and an irreversible red color appears from 16°C. The thermal maximum of the melting peak of 24 (1212) is at 20.5°C.

Commercial fermentation One power toe 〇－ r] international search report ANNEX To’hdE INTERNATIONAL 5EAtCHRE PORT JN

Claims (7)

[Claims] 1. Monomers of formula (I) or mixtures of such monomers exhibit irreversible thermochromism. consisting of at least one polydiacetylene obtained by polymerization of a compound, said one or A temperature indicator in which multiple monomers are in a crystalline state. CH3-(CH2)n-C≡C-C≡C-(CH2)n'-CH3(I) In the formula, n and n' represent the same or different integers between 2 and 21. 2. Claim 1, wherein the monomer is in the form of a polycrystalline film or a single crystal in a crystallized state. Temperature indicator listed. 3. The polydiacetylene compound is a diacetylene compound of formula (I) according to claim 1. obtained by photopolymerization of at least one of the renic monomers and by irradiation with high-energy radiation. The temperature indicator according to claim 1 or 2, which is a temperature indicator according to claim 1 or 2. 4. The polydiacetylene compound is a diacetylene compound corresponding to a polydiacetylene polymer. Claims 1 to 3 which are mixtures with ren monomers or monomer mixtures The temperature indicator according to any one of the items. 5. The polydiacetylene compound is disposed in the form of a thin film on a chemically inert substrate. A temperature indicator according to any one of claims 1 to 4. 6. The polydiacetylene compound is mixed with a thermoplastic in a molten state. After that, at least one diacetylenic monomer of formula (I) according to claim 1 Claims obtained by photopolymerization of, by irradiation with high-energy irradiation The temperature indicator according to any one of items 1 to 5. 7. The polydiacetylene compound contains at least one monomer of formula (I) with 580 and light with UV irradiation for a sufficient period of time to give an absorption peak between 650 nm and 650 nm. The product described in any one of claims 1 to 5 is obtained by polymerization. temperature indicator.